7/23/2019 Lec STARCCM FoundationTrainingV2.0
1/342
CD-adapco, Americas Agency Training Document CFD Basics - 1
CFD Basics - Outline
CFD Basics Introduction
CAD to Solution overview Governing Equations
Initial and Boundary Conditions Turbulence Modeling Solution of Governing Equations
Convergence Monitoring Errors in CFD Analysis Non-Dimensional Numbers Mesh Generation
Post-Processing Divergence
Ensuring Quality of a CFD analysis CD-adapco solvers
Which Solver Do I Choose for my Application
7/23/2019 Lec STARCCM FoundationTrainingV2.0
2/342
CD-adapco, Americas Agency Training Document CFD Basics - 2
CFD Basics
Introduction to CFD
Governing equations of fluid flow and heat transfer
Boundary Conditions
Meshing Guidelines
Solution best practices
STAR Workflow overview
7/23/2019 Lec STARCCM FoundationTrainingV2.0
3/342
CD-adapco, Americas Agency Training Document CFD Basics - 3
CFD Basics
What is CFD?
CFD is Computational Fluid Dynamics
Computational numerical methods
PC, workstation, cluster
Fluid
gas or liquid: Material that deforms continuously underapplication of a shear stress
Dynamics
Moving (as opposed to static)
7/23/2019 Lec STARCCM FoundationTrainingV2.0
4/342
CD-adapco, Americas Agency Training Document CFD Basics - 4
CFD Basics Need For CFD
Why do we need CFD?
Very few fluid mechanics problems have analytical
solutions (e.g. Laminar flow between parallel plates,laminar flow between rotating cylinders).
Most real world problems do not have a closed formsolution, and require a numerical solution.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
5/342
CD-adapco, Americas Agency Training Document CFD Basics - 5
CFD Basics Applications where CFD is used
What are some of the areas in which CFD is used?
- Aerospace
- Automotive- Biomedical
- Building
- Civil Engineering
- Chemical Process- Environmental
- Marine
- Power Generation
- Sport Equipment
- Turbomachinery
7/23/2019 Lec STARCCM FoundationTrainingV2.0
6/342
CD-adapco, Americas Agency Training Document CFD Basics - 6
CFD Basics - ELEMENTS OF 3D CFD SIMULATION
conservationequations
turbulence
model
spray model
combustion
model
wall film
model
mathematicalmodel
(differential)
finite volume
discretisation
solution
algorithm
finite volumemodel
initial/boundary
conditions*
movingmesh*
CFD cpdeSTAR-CD
operating
conditions*
solutioncontrols*
RESULTScomputer
post-processing*
optimisation
CADgeometry*
*via STAR-CD or STAR-CCM+
7/23/2019 Lec STARCCM FoundationTrainingV2.0
7/342
CD-adapco, Americas Agency Training Document CFD Basics - 7
CFD Basics CAD to Solution Overview
1. CAD Modeler
2. CAD Importer
3. Pre-Processor
4. Solver
5. Post-Processor
CADCAD
CFDCFD
Meshing
Pre/Post
/Solution
COMPONENTFUNCTION
Geometry Building
Geometry Import and Mesh Generation
Physics and Boundary Conditions
Run Analysis
Solution Revealed to User
Discipline CFDSOFTWARE
7/23/2019 Lec STARCCM FoundationTrainingV2.0
8/342
CD-adapco, Americas Agency Training Document CFD Basics - 8
CFD Basics CAD to Solution
1 h
4 h
2 h
8 h
CAD Geometry
Surface Clean-up
Surface Meshing
Volume Meshing
CFD Solution
Post-processing
1 h
7/23/2019 Lec STARCCM FoundationTrainingV2.0
9/342
CD-adapco, Americas Agency Training Document CFD Basics - 9
CFD Basics Governing Equations Conservation Laws
The following equations are fundamental to CFD:
Conservation of Mass(continuity)
Conservation of Momentum(F=ma)
Conservation of Energy(1st Law of Thermodynamics)
In addition, depending on complexity of the problem (e.g. ifturbulent), additional transport equations are solved.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
10/342
CD-adapco, Americas Agency Training Document CFD Basics - 10
CFD Basics Governing Equations ConstitutiveRelationships
In order to close the system of equations (laws of conservation), we need the responseof materials to external effects (i.e. surface forces, heat or mass fluxes). These aredescribed by constitutive relationships.
Stokes LawExpresses relationship between stresses and rate of deformation for fluids:
is the dynamic viscosity, P is the pressure, V is the velocity vector and I is the identitytensor.
Fouriers LawExpresses relationship between heat flux and temperature gradient
Where k is the thermal conductivity
Tk-q =
( ) IPIV.2D2rrr
= ( )[ ]T
VV2
1D
rr
+=
7/23/2019 Lec STARCCM FoundationTrainingV2.0
11/342
CD-adapco, Americas Agency Training Document CFD Basics - 11
CFD Basics Governing Equations Equation of State
Additional requirement for closure of governing equations.
The equation of state links density and internal energy tothe basic thermodynamic variables p (pressure) and T(temperature)
= (p,T); e = e(p,T)
7/23/2019 Lec STARCCM FoundationTrainingV2.0
12/342
CD-adapco, Americas Agency Training Document CFD Basics - 12
CFD Basics Governing Equations General Form
=1 mass =u,v,w momentum = e energy A is the surface area V is the volume S is the source term
V VS S
dVSAdAdudVt VSSV +=+
r
CONSERVATION:
7/23/2019 Lec STARCCM FoundationTrainingV2.0
13/342
CD-adapco, Americas Agency Training Document CFD Basics - 13
CFD Basics Governing Equations
/t dV + u dA = dA + S dV
Rate of change of
quantity in ControlVolume
Convective Flux
Diffusion Flux
Volumetric Source
V VS S
7/23/2019 Lec STARCCM FoundationTrainingV2.0
14/342
CD-adapco, Americas Agency Training Document CFD Basics - 14
CFD Basics Convection and Diffusion
u dA
CONVECTION
dA
DIFFUSION
u
7/23/2019 Lec STARCCM FoundationTrainingV2.0
15/342
CD-adapco, Americas Agency Training Document CFD Basics - 15
CFD Basics Initial and Boundary Conditions
To complete our mathematical model, conditions on thesolution domain boundaries have to be specified.
Conditions related to start time are called InitialConditions.
Conditions related to space are called BoundaryConditions.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
16/342
CD-adapco, Americas Agency Training Document CFD Basics - 16
CFD Basics Boundary Conditions - Types
Dirichlet Boundary Conditionsare BCs where value ofthe dependent variable at the boundary is given (e.g. inlet
velocity of fluid).
Neumann Boundary Conditionsare BCs where gradientof the dependent variable at the boundary is specified.
It is possible that for the same boundary, Dirichlet BCs areapplied for some dependent variables, and Neumann BCs
are applied for other dependent variables.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
17/342
CD-adapco, Americas Agency Training Document CFD Basics - 17
CFD Basics Boundary Conditions (External flow)
7/23/2019 Lec STARCCM FoundationTrainingV2.0
18/342
CD-adapco, Americas Agency Training Document CFD Basics - 18
CFD Basics Boundary Conditions External FlowExamples
- Flow over an aircraft or automobile
- Flow over a cylinder
- Flow around buildings
7/23/2019 Lec STARCCM FoundationTrainingV2.0
19/342
CD-adapco, Americas Agency Training Document CFD Basics - 19
CFD Basics Boundary Conditions (External Flow)
FreeStreamFreeStreamFreeStreamFreeStream
InletInletInletInlet OutletOutletOutletOutlet
NoslipWallNoslipWallNoslipWallNoslipWall
7/23/2019 Lec STARCCM FoundationTrainingV2.0
20/342
CD-adapco, Americas Agency Training Document CFD Basics - 20
CFD Basics Boundary Conditions Free Stream
7/23/2019 Lec STARCCM FoundationTrainingV2.0
21/342
CD-adapco, Americas Agency Training Document CFD Basics - 21
CFD Basics Boundary Conditions
Inlet Boundaries can be specified at portions of boundary where thefluid enters the solution domain, and where the velocity and scalar(temperature, species concentration, turbulence quantities)
distributions is known.
Outlet Boundaries can be specified at that portion of the solutiondomain, where flow leaves the domain. It assumes zero gradient of all
dependent variables in the flow direction.
No-Slip Wall requires prescription of velocity at the wall (e.g. zerovelocity for a stationary wall).
Free Stream boundary represents the conditions at a far-field location(i.e. At the periphery of a bubble of fluid surrounding a moving object)
7/23/2019 Lec STARCCM FoundationTrainingV2.0
22/342
CD-adapco, Americas Agency Training Document CFD Basics - 22
CFD Basics Boundary Conditions PressureBoundaries
Pressure boundary conditions can be specified at boundarieswhere the pressure distribution is known.
Boundary velocities are obtained from Neumann Boundary conditionfor velocity.
All dependent variables are either specified or extrapolated from theinside using zero gradient assumption. At outflow, all variables areextrapolated.
Note: The velocity at the pressure boundary where the flow comes inhas to be sub-sonic, or else the upstream velocity needs to bespecified, thus violating the Neumann boundary condition.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
23/342
CD-adapco, Americas Agency Training Document CFD Basics - 23
Day 1 : CFD Basics Boundary Conditions - InternalFlow
7/23/2019 Lec STARCCM FoundationTrainingV2.0
24/342
CD-adapco, Americas Agency Training Document CFD Basics - 24
CFD Basics Boundary Conditions Internal Flow -Examples
- Flow inside ducts
- Flow inside Intake/Exhaust manifolds
- Flow inside coolant jackets
- Flow inside human blood vessels
- In-Cylinder flow of IC engines
7/23/2019 Lec STARCCM FoundationTrainingV2.0
25/342
CD-adapco, Americas Agency Training Document CFD Basics - 25
CFD Basics Boundary Conditions Internal Flow
InletInletInletInletOutletOutletOutletOutlet
Noslipwall(u=0)Noslipwall(u=0)Noslipwall(u=0)Noslipwall(u=0)
Adiabatic,fixedAdiabatic,fixedAdiabatic,fixedAdiabatic,fixedtemperature,ortemperature,ortemperature,ortemperature,or
fixedheatflux.fixedheatflux.fixedheatflux.fixedheatflux.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
26/342
CD-adapco, Americas Agency Training Document CFD Basics - 26
CFD Basics Boundary Conditions - Inlets
Velocity and Scalars can be specified for an inlet.
u v
w
x
y
x
y
7/23/2019 Lec STARCCM FoundationTrainingV2.0
27/342
CD-adapco, Americas Agency Training Document CFD Basics - 27
CFD Basics Boundary Conditions - Outlet
n is the unit normal.
Gradients of all variablesalong flow direction is takento be zero.
Mass flow is fixed fromoverall continuity.
n
FLOW SPLITorMASS FLOW RATE
7/23/2019 Lec STARCCM FoundationTrainingV2.0
28/342
CD-adapco, Americas Agency Training Document CFD Basics - 28
CFD Basics - Outlet Boundary Conditions
10L
L
Zone ofZone of
Recirculation:Recirculation:Area is
inaccurate
DevelopingDeveloping
Zone:Zone:
Area has littleaccuracy
DevelopedDeveloped
Zone:Zone:
Area isaccurate
3L-8L
Flowdirection
7/23/2019 Lec STARCCM FoundationTrainingV2.0
29/342
CD-adapco, Americas Agency Training Document CFD Basics - 29
CFD Basics Boundary Conditions - Symmetry
n
SymmetryplaneindicatesasurfacewherenormalvelocityandnorSymmetryplaneindicatesasurfacewherenormalvelocityandnorSymmetryplaneindicatesasurfacewherenormalvelocityandnorSymmetryplaneindicatesasurfacewherenormalvelocityandnormalmalmalmal
velocitygradientsareallzero.(nindicatestheunitnormal)velocitygradientsareallzero.(nindicatestheunitnormal)velocitygradientsareallzero.(nindicatestheunitnormal)velocitygradientsareallzero.(nindicatestheunitnormal)
7/23/2019 Lec STARCCM FoundationTrainingV2.0
30/342
CD-adapco, Americas Agency Training Document CFD Basics - 30
CFD Basics Boundary Conditions - Periodic
AperiodicboundaryconditionreferstoapairAperiodicboundaryconditionreferstoapairAperiodicboundaryconditionreferstoapairAperiodicboundaryconditionreferstoapair
ofboundarieswheretheflowrepeatsitself.ofboundarieswheretheflowrepeatsitself.ofboundarieswheretheflowrepeatsitself.ofboundarieswheretheflowrepeatsitself.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
31/342
CD-adapco, Americas Agency Training Document CFD Basics - 31
CFD Basics Gallery of Turbulence
7/23/2019 Lec STARCCM FoundationTrainingV2.0
32/342
CD-adapco, Americas Agency Training Document CFD Basics - 32
CFD Basics - Turbulence
Most of the commonly occurring flows are turbulent innature (e.g. Jet streams, combustion, boundary layers onwings of aircraft etc.). Turbulence by itself is difficult todefine, but typically has the following characteristics:
- Irregular(hence requires statistical methods)
- Diffusive(causes rapid mixing)- Large Reynolds numbers
- Three dimensional vorticity fluctuations
- Dissipative(exhibits viscous losses, and needs acontinuous supply of energy to make up for losses)
7/23/2019 Lec STARCCM FoundationTrainingV2.0
33/342
CD-adapco, Americas Agency Training Document CFD Basics - 33
CFD Basics - Why do we need turbulence models?
Turbulence is influenced by structures having large lengthscales, and small length scales (down to the molecular
level). To resolve all scales, the number of computationalcells is approximately (Re3), which is beyond thecomputing resources currently available.
In order to model scales smaller than the computationalcell size, turbulence models are required.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
34/342
CD-adapco, Americas Agency Training Document CFD Basics - 34
CFD Basics - Turbulence
= = (t) dt
(t)=+ (t)
t
t1
0
High Reynolds Number u(t) = U + u(t)
t
u
u(t) U u'(t)
7/23/2019 Lec STARCCM FoundationTrainingV2.0
35/342
CD-adapco, Americas Agency Training Document CFD Basics - 35
CFD Basics - TURBULENCE MODELLING OPTIONS
Eddy Viscosity Models
1. Linear k- models: standard, RNG, Chen low- and high-Re variants of k-
2. V2F model3. Non-linear models: quadratic and cubic k-, several variants low- and high-Re Suga Speziale quadratic
4. Other k-: standard and SST, low- and high-Re Spalart-Almaras
ReynoldsStressTransportmodelsReynoldsStressTransportmodelsReynoldsStressTransportmodelsReynoldsStressTransportmodels
1. GibsonandLaunder
2. Craft
3. Speziale,Sarker andGatski
7/23/2019 Lec STARCCM FoundationTrainingV2.0
36/342
CD-adapco, Americas Agency Training Document CFD Basics - 36
CFD Basics - TURBULENCE MODELING OPTIONS
Detached Eddy Simulation
- In regions of irrotational flow, RANS is used
- In regions of detached eddies, LES is used
- Accurate for capturing eddies created by bluff bodies
- Excellent compromise between RANS and LES
Large Eddy Simulation
- Resolves the large scale eddies- Uses a sub-grid scale model for small eddies
- Requires very fine mesh
DNS
- Models all eddies from large scale to small scale- Not practical for industrial applications
7/23/2019 Lec STARCCM FoundationTrainingV2.0
37/342
CD-adapco, Americas Agency Training Document CFD Basics - 37
CFD Basics Inlet Turbulence
Turbulence conditions at inlet are seldom known.
If inlet is sufficiently upstream of region of interest, results
are insensitive to inlet turbulence. If inlet is close to region of interest, need to perform a
sensitivity study of inlet turbulence on results.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
38/342
CD-adapco, Americas Agency Training Document CFD Basics - 38
CFD Basics Inlet Turbulence
Estimation of Inlet Turbulence:
Intensity of turbulence I Length of turbulence scale L
Common Practice
I 0.03 - 0.10 L Dh/10Dh is hydraulic diameterC = 0.09 L
kC
VI2
3k
3/23/4
22
=
=
7/23/2019 Lec STARCCM FoundationTrainingV2.0
39/342
CD-adapco, Americas Agency Training Document CFD Basics - 39
CFD Basics Turbulence Wall Treatment
Near wall treatment for turbulence models is typically chosenbased on the local non-dimensional distance of the cell centroidof the near wall cell from the wall (y+).
Whereyisthedistanceofthenearwallcellcentroid fromthewall,kis
thelocalturbulencekineticenergy,andC isaconstanthavingavalueof
0.09.
y/kCy1/21/4=+
7/23/2019 Lec STARCCM FoundationTrainingV2.0
40/342
CD-adapco, Americas Agency Training Document CFD Basics - 40
CFD Basics Turbulence Wall Treatment
Wall Functions
Computationally efficient
Uses logarithmic law of the wall
Requires y+ to be in the 30 200 range
Applies only to attached flows and fails in recirculating flows
Low Reynolds number approach
Computationally expensive
Integrates down to the wall and uses no-slip Requires near wall y+ less than 5
Hybrid Treatment
If y+ < 5, use Low Re approach
If y+ > 30 use Wall Function approach If 5 < y+ < 30 blend smoothly between two approaches
7/23/2019 Lec STARCCM FoundationTrainingV2.0
41/342
CD-adapco, Americas Agency Training Document CFD Basics - 41
CFD Basics - Estimation of Near Wall Cell Thickness
How can I get an approximate estimate of the nearwall cell thickness?
y+ = C1/4 k1/2 y /
1. Estimate k from free stream velocity and an assumedturbulence intensity (1.5 * I2 U2)
2. Substitute the required y+ value in the equation, and getan estimate of y.
Note: C=0.09
7/23/2019 Lec STARCCM FoundationTrainingV2.0
42/342
CD-adapco, Americas Agency Training Document CFD Basics - 42
CFD Basics - Choosing a turbulence Model
Spallart Almaras Turbulence Model
Recommended when flow is primarily attached with no separation, ormild separation. e.g. For flow over a wing or a fueslage.
k- or k- Turbulence Model
Common industrial applications, with flow separation and recirculation.
Reynolds Stress Model
When the turbulence is highly anisotropic. e.g. In a Cyclone separator.
Detached Eddy SimulationRecommended for aeroacoustic applications
7/23/2019 Lec STARCCM FoundationTrainingV2.0
43/342
CD-adapco, Americas Agency Training Document CFD Basics - 43
CFD Basics - Choosing a Turbulence Model
7/23/2019 Lec STARCCM FoundationTrainingV2.0
44/342
CD-adapco, Americas Agency Training Document CFD Basics - 44
CFD Basics - Choosing a Turbulence Model
What is our recommendation on choosing a turbulence model?
Choose the simplest model which gives acceptable engineering resultsfor your application. Typically start with the k- turbulence model. If wall
effects are important, use either the hybrid wall functions, or a lowReynolds number turbulence model, making sure to have a fine meshresolution in the wall region. If anisotropic effects are important, thenuse Reynolds Stress Models.
What factors other than a turbulence model affect accuracy of asimulation?
- Inlet values of turbulence chosen
- Size and quality of the computational grid
7/23/2019 Lec STARCCM FoundationTrainingV2.0
45/342
CD-adapco, Americas Agency Training Document CFD Basics - 45
CFD Basics - Discretization
In order to obtain a solution for the governing equations, themathematical model (equations and constitutive relationships) istransformed into a system of algebraic equations.
Special techniques are used for the transient, convection,diffusion and source terms in this process.
The discretized equations have the form expressed in theequation below. C denotes cell center value, and k denotesvalues in neighboring cells.
=+k
ckkcc QAA
7/23/2019 Lec STARCCM FoundationTrainingV2.0
46/342
CD-adapco, Americas Agency Training Document CFD Basics - 46
CFD Basics Solution of Discretized Equations
The discretized equations are coupled and non-linear. Thediscretized equations are then solved using iterative
methods.
Steady State problems typically use the SIMPLE algorithm,and transient problems either use SIMPLE or PISO
algorithms.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
47/342
CD-adapco, Americas Agency Training Document CFD Basics - 47
CFD Basics SIMPLE Algorithm
What does SIMPLE stand for?
Semi-Implicit Method for Pressure Linked Equations
A variation of the SIMPLE algorithm is used in all CD-adapco solvers for solving the equations of fluid flow andheat transfer. (Note that STAR V3.26 uses the PISOalgorithm (Pressure Implicit Split Operator) for transientanalysis)
7/23/2019 Lec STARCCM FoundationTrainingV2.0
48/342
CD-adapco, Americas Agency Training Document CFD Basics - 48
CFD Basics SIMPLE Algorithm
Main Steps in SIMPLE:
1. Variables are assigned initial values at startup, and time is advanced by dt(time step).
2. With the initially guessed pressure field, the momentum equations are solved,to obtain an approximate velocity field.
3. The velocity field computed in step 2 along with the prevailing density is usedto compute new mass fluxes, and then solve the mass conservation (pressurecorrection equation). This results in corrections for velocities, density andpressure being computed and applied.
4. If applicable, additional transport equations (turbulence, energy, speciesconcentration) are solved.
5. If necessary, fluid properties (e.g. density, viscosity, Prandtl number areupdated).
6. Steps 2 through 5 constitute an outer iteration. These steps are repeated until
the residual level before the first inner iteration in each equation becomessufficiently small.
7. When the non-linear coupled equations are satisfied to a desired tolerance,time is advanced by dt, and the process is repeated.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
49/342
CD-adapco, Americas Agency Training Document CFD Basics - 49
CFD Basics Under-relaxation
In order to promote stability of the solution method, an under-relaxation is done for all variables (other than the pressurecorrection).
In the equations below, k+1 refers to the most recent iteration ortime step, and k refers to the prior iteration or time step. Omega isthe under-relaxation factor, having a value between 0 and 1.
CFD B i C M i i
7/23/2019 Lec STARCCM FoundationTrainingV2.0
50/342
CD-adapco, Americas Agency Training Document CFD Basics - 50
CFD Basics Convergence Monitoring
There are two main criteria for convergence monitoring:
1. Make sure that the global residuals reduce by 2-3 orders
of magnitude (applies only if starting with a zero solutionin the domain, or a simple initial guess).
2. Monitor of engineering quantities of interest (e.g. dragcoefficient, pressure rise across a fan, pressure drop
across a heat exchanger) and make sure that they do notchange with iteration.
We need to make sure that both of the above criteria aremet before we declare our solution to be converged.
CFD B i C M it i
7/23/2019 Lec STARCCM FoundationTrainingV2.0
51/342
CD-adapco, Americas Agency Training Document CFD Basics - 51
CFD Basics Convergence Monitoring
ResidualsResidualsResidualsResiduals OutletTemperatureOutletTemperatureOutletTemperatureOutletTemperature
CFD B i E i CFD
7/23/2019 Lec STARCCM FoundationTrainingV2.0
52/342
CD-adapco, Americas Agency Training Document CFD Basics - 52
CFD Basics Errors in CFD
The following are the main types of errors in a CFD analysis:
Modeling Errors This is the difference between the actual flow and
the exact solution of the model equations (Navier stokes or RANSequations)
Discretization Errors This is the difference between the exact
solution of the differential equation, and the exact solution of thealgebraic system of equations obtained by discretizing them.
Iteration Errors This is the difference between the iterative and
exact solution of the algebraic equation systems.
CFD B i M d li g E
7/23/2019 Lec STARCCM FoundationTrainingV2.0
53/342
CD-adapco, Americas Agency Training Document CFD Basics - 53
CFD Basics Modeling Errors
In case of turbulent flows in complex geometries, modelingerrors are mainly due to imperfections in the turbulencemodel and to simplifications in the geometry or boundaryconditions.
How can modeling errors be estimated?
Compare solutions in which discretization and iterationerrors are negligible, with accurate experimental data, ordata obtained by more accurate models (e.g. Direct
Numerical Simulation).
CFD Basics Discretization Errors
7/23/2019 Lec STARCCM FoundationTrainingV2.0
54/342
CD-adapco, Americas Agency Training Document CFD Basics - 54
CFD Basics Discretization Errors
Discretization errors can be estimated by performing asystematic grid refinement and comparing the solutionsobtained on a sequence of grids. The errors areproportional to the difference in solution obtained onconsecutive grids.
CFD Basics Iterative Errors
7/23/2019 Lec STARCCM FoundationTrainingV2.0
55/342
CD-adapco, Americas Agency Training Document CFD Basics - 55
CFD Basics Iterative Errors
The level of iterative errors can be reliably controlled bymonitoring the residual norms (either sum of absolutevalues, or the square root of the sum of squares ofresiduals in all Control Volumes).
It is not the level of the residual itself, but the amount of
reduction compared to initial levels that is important.
CFD Basics Non Dimensional Numbers
7/23/2019 Lec STARCCM FoundationTrainingV2.0
56/342
CD-adapco, Americas Agency Training Document CFD Basics - 56
CFD Basics Non Dimensional Numbers
Next we briefly overview some important non-dimensionalnumbers that are used in CFD.
CFD Basics Laminar vs Turbulent
7/23/2019 Lec STARCCM FoundationTrainingV2.0
57/342
CD-adapco, Americas Agency Training Document CFD Basics - 57
CFD Basics Laminar vs Turbulent
Reynolds Number = Inertia Force / Viscous force
Reynolds Number = ( * U * L)/
( is the density, U is a characteristic velocity, L is a characteristiclength scale, and is the laminar viscosity)
If Reynolds number is low, flow is laminar (viscous forces dominate)
If Reynolds number is high, flow is turbulent
e.g.For pipe flows: Re > 2300 implies turbulent flow
For flat plate: Re > 5e5 implies turbulent flow
CFD Basics Compressible vs Incompressible
7/23/2019 Lec STARCCM FoundationTrainingV2.0
58/342
CD-adapco, Americas Agency Training Document CFD Basics - 58
CFD Basics Compressible vs Incompressible
Mach Number = speed of flow / speed of sound
If Mach Number is above 0.3, need to model ascompressible.
In low speed flows, if temperature change causes achange in density, then flow should be modeled ascompressible.
CFD Basics Natural vs Force Convection
7/23/2019 Lec STARCCM FoundationTrainingV2.0
59/342
CD-adapco, Americas Agency Training Document CFD Basics - 59
CFD Basics Natural vs Force Convection
Gr/Re2 = Buoyancy Force / Inertia Force
Grashof Number / Reynolds Number
2
= g *
*
T / (U
2
)
Where g is gravity, is the coefficient of volumeexpansion, T is the difference in temperature between
the surface and the free stream, U is the free streamvelocity.
If Gr/Re2 >> 1, then effect of buoyancy is important
If Gr/Re2
7/23/2019 Lec STARCCM FoundationTrainingV2.0
60/342
CD-adapco, Americas Agency Training Document CFD Basics - 60
CFD Basics Conduction vs Convection
Biot Number = Resistance of conduction / Resistanceof convection
Biot Number = (L/k) / (1/h)
Where L is the thickness of the body, k is the thermalconductivity, and h is the heat transfer coefficient.
If Bi >> 1, wall side resistance is large, and wall conductionshould be included
If Bi
7/23/2019 Lec STARCCM FoundationTrainingV2.0
61/342
CD-adapco, Americas Agency Training Document CFD Basics - 61
CFD Basics Mesh Generation
Solid Fluid
Meshing: ......of the Surface
...of the Volume
(calculation)
CAD MESHER
CFD Basics Mesh Generation
7/23/2019 Lec STARCCM FoundationTrainingV2.0
62/342
CD-adapco, Americas Agency Training Document CFD Basics - 62
CFD Basics Mesh Generation
The quality of a CFD solution is dependent on the quality ofthe underlying volume mesh.
Hence it is important to ensure a good quality volumemesh (which requires a good quality surface mesh)
CFD Basics - Elements of Surface Meshing
7/23/2019 Lec STARCCM FoundationTrainingV2.0
63/342
CD-adapco, Americas Agency Training Document CFD Basics - 63
C as cs e e ts o Su ace es g
Arbitrary Polygonquad
triangle
CFD Basics - Surface Mesh Quality
7/23/2019 Lec STARCCM FoundationTrainingV2.0
64/342
CD-adapco, Americas Agency Training Document CFD Basics - 64
y
LOW QUALITY HIGH QUALITYEquilateraltrianglesimplygoodqualityEquilateraltrianglesimplygoodqualityEquilateraltrianglesimplygoodqualityEquilateraltrianglesimplygoodquality.
CFD Basics - Surface Mesh Quality
7/23/2019 Lec STARCCM FoundationTrainingV2.0
65/342
CD-adapco, Americas Agency Training Document CFD Basics - 65
y
LOW QUALITY HIGH QUALITYIftheanglebetweenthefacenormalandthevectorjoiningadjaIftheanglebetweenthefacenormalandthevectorjoiningadjaIftheanglebetweenthefacenormalandthevectorjoiningadjaIftheanglebetweenthefacenormalandthevectorjoiningadjacentcellcentcellcentcellcentcell
centroidscentroidscentroidscentroids issmall,thetrianglequalityishigh.issmall,thetrianglequalityishigh.issmall,thetrianglequalityishigh.issmall,thetrianglequalityishigh.
CFD Basics Surface Mesh
7/23/2019 Lec STARCCM FoundationTrainingV2.0
66/342
CD-adapco, Americas Agency Training Document CFD Basics - 66
What are the requirements of a surface mesh, in orderto get a valid volume mesh using CD-adapco automesh tools?
- Surface is closed (water tight)
- Triangles are connected one to one
- Surface is manifold (Only two cells connected to an edge)
CFD Basics Basic Volume Mesh Elements
7/23/2019 Lec STARCCM FoundationTrainingV2.0
67/342
CD-adapco, Americas Agency Training Document CFD Basics - 67
ArbitraryPolyhedral
Prismatic
Pyramid
Hexahedral
Tetrahedral
Day 1 CFD Basics Volume Mesh Types
7/23/2019 Lec STARCCM FoundationTrainingV2.0
68/342
CD-adapco, Americas Agency Training Document CFD Basics - 68
Generally mesh generation is done either using manualtechniques (e.g. in pro-STAR) or using an auto-mesher(e.g. ammbatch)
When do we need manual meshing?
- If we need a structured mesh (for cell layer addition and
deletion)
- If we have very tight gaps (e.g. nominal cell size is 2mm,but gaps are of the order of 0.05 mm)
CFD Basics Volume Mesh Types
7/23/2019 Lec STARCCM FoundationTrainingV2.0
69/342
CD-adapco, Americas Agency Training Document CFD Basics - 69
What are the mesh types that can be generated by CD-adapco auto meshers?
Trim Mesh Least demanding on surface quality
Polyhedral Mesh
As automated as a tetrahedral mesher
Numerically more stable, less diffusive, and more accurate
than an equivalent tetrahedral mesh
Hybrid Mesh
Tetrahedral mesh
CFD Basics Volume Mesh Types
7/23/2019 Lec STARCCM FoundationTrainingV2.0
70/342
CD-adapco, Americas Agency Training Document CFD Basics - 70
Trim Mesh
CFD Basics Volume Mesh Types
7/23/2019 Lec STARCCM FoundationTrainingV2.0
71/342
CD-adapco, Americas Agency Training Document CFD Basics - 71
When is a trim mesh recommended?
1. If an underlying custom mesh needs to be used (e.g. forturbo machinery applications, a basic bodyfittedstructured mesh can be used as a template for creating avolume mesh with additional details.)
2. If surface quality is not good enough for a polyhedralmesh.
CFD Basics Volume Mesh Types
7/23/2019 Lec STARCCM FoundationTrainingV2.0
72/342
CD-adapco, Americas Agency Training Document CFD Basics - 72
Polyhedral Mesh
CFD Basics Volume Mesh Types
7/23/2019 Lec STARCCM FoundationTrainingV2.0
73/342
CD-adapco, Americas Agency Training Document CFD Basics - 73
When is a polyhedral mesh recommended?
1. If the quality of surface mesh is excellent.2. If process of mesh generation needs to be highly
automated (as automated as a tetrahedral mesh).
CFD Basics Volume Mesh Types
7/23/2019 Lec STARCCM FoundationTrainingV2.0
74/342
CD-adapco, Americas Agency Training Document CFD Basics - 74
Tetrahedral Mesh
CFD Basics Volume Mesh Types
7/23/2019 Lec STARCCM FoundationTrainingV2.0
75/342
CD-adapco, Americas Agency Training Document CFD Basics - 75
When is a tetrahedral mesh recommended?
The only scenario where a tetrahedral mesh isrecommended is when comparisons have to be made withlegacy tetrahedral models.
CFD Basics Advantages of Polyhedral Mesh overTetrahedral Mesh
7/23/2019 Lec STARCCM FoundationTrainingV2.0
76/342
CD-adapco, Americas Agency Training Document CFD Basics - 76
Mesh dependency performedby successively halvingsurface triangulation size from
20mm to 0.625mm Convergence judged from
pressure drop across jacket
CFD Basics Advantages of Polyhedral Meshover Tetrahedral Mesh
7/23/2019 Lec STARCCM FoundationTrainingV2.0
77/342
CD-adapco, Americas Agency Training Document CFD Basics - 77
21,87221,87221,87221,872
POLYSPOLYSPOLYSPOLYS
39,58739,58739,58739,587
TETSTETSTETSTETS
593,888593,888593,888593,888
POLYSPOLYSPOLYSPOLYS
2,322,1062,322,1062,322,1062,322,106
TETSTETSTETSTETS
CFD Basics Advantages of Polyhedral Mesh
over Tetrahedral Mesh
7/23/2019 Lec STARCCM FoundationTrainingV2.0
78/342
CD-adapco, Americas Agency Training Document CFD Basics - 78
ContoursofStaticContoursofStaticContoursofStaticContoursofStatic
PressurePressurePressurePressure
593,888593,888593,888593,888
POLYSPOLYSPOLYSPOLYS2,322,1062,322,1062,322,1062,322,106
TETSTETSTETSTETS
CFD Basics Advantages of Polyhedral Meshover Tetrahedral Mesh
7/23/2019 Lec STARCCM FoundationTrainingV2.0
79/342
CD-adapco, Americas Agency Training Document CFD Basics - 79
3
4
5
6
7
10000 100000 1000000 10000000
Number of Cells
Delta
P(
kPa)
POLYPOLYPOLYPOLYTETTETTETTET
MESHDEPENDENCYMESHDEPENDENCYMESHDEPENDENCYMESHDEPENDENCY
43.25hours43.25hours43.25hours43.25hours
10hours10hours10hours10hours1.6hours1.6hours1.6hours1.6hours
5%error
Run on a 3GhzDual Processorworkstation with2GB RAM
CFD Basics Volume Mesh Quality
7/23/2019 Lec STARCCM FoundationTrainingV2.0
80/342
CD-adapco, Americas Agency Training Document CFD Basics - 80
High QualityLow Quality
Diffusion
Conve
ction
CFD Basics Volume Mesh Quality
7/23/2019 Lec STARCCM FoundationTrainingV2.0
81/342
CD-adapco, Americas Agency Training Document CFD Basics - 81
Accuracy of Convection
- When using linear interpolation for convective fluxes, thelines connecting neighboring faces should pass throughthe center of the common face.
Accuracy of Diffusion
- Maximum accuracy of diffusive fluxes is achieved when theline connecting neighbor cell centers is orthogonal to thecell face, and also passes through the center of the
common face.
CFD Basics Grid Generation Guidelines
7/23/2019 Lec STARCCM FoundationTrainingV2.0
82/342
CD-adapco, Americas Agency Training Document CFD Basics - 82
General Guidelines on Grid Generation
~5 control volumes across a shear layer ~5 control volumes across a separated region
At Least 4 control volumes across a flow passage
Vary grid spacing gradually
Keep aspect ratio reasonable (Less than 1:10 wheneverpossible)
CFD Basics Grid Generation Guidelines
7/23/2019 Lec STARCCM FoundationTrainingV2.0
83/342
CD-adapco, Americas Agency Training Document CFD Basics - 83
InsufficientmeshInsufficientmeshInsufficientmeshInsufficientmesh
resolutiontoresolveresolutiontoresolveresolutiontoresolveresolutiontoresolve
flow.flow.flow.flow.
RefinementenablesbetterRefinementenablesbetterRefinementenablesbetterRefinementenablesbetter
resolutionoftheflow.resolutionoftheflow.resolutionoftheflow.resolutionoftheflow.
CFD Basics - Post-Processing
7/23/2019 Lec STARCCM FoundationTrainingV2.0
84/342
CD-adapco, Americas Agency Training Document CFD Basics - 84
Reporting
Drag / Lift Coefficients
Heat Rejection by heat exchanger
Pressure rise across a fan or compressor Pressure drop in a duct
Swirl, tumble, burn rate in an IC engine
Flow Visualization Visualization of Fields
Scalar Quantities
Vector Quantities
Streamlines
Iso-Surfaces
Animation
CFD Basics Reporting and Monitoring
7/23/2019 Lec STARCCM FoundationTrainingV2.0
85/342
CD-adapco, Americas Agency Training Document CFD Basics - 85
ResidualConvergenceResidualConvergenceResidualConvergenceResidualConvergence
FieldValuesFieldValuesFieldValuesFieldValuesDrag/LiftMonitoringDrag/LiftMonitoringDrag/LiftMonitoringDrag/LiftMonitoring
CenterlineCpCenterlineCpCenterlineCpCenterlineCp
CFD Basics Post Processing Scalars and Vectors
7/23/2019 Lec STARCCM FoundationTrainingV2.0
86/342
CD-adapco, Americas Agency Training Document CFD Basics - 86
CFD Basics Post-processing Surface Plot Coefficient of Pressure
7/23/2019 Lec STARCCM FoundationTrainingV2.0
87/342
CD-adapco, Americas Agency Training Document CFD Basics - 87
CFD Basics : Post-Processing Capabilities: Streamlines
7/23/2019 Lec STARCCM FoundationTrainingV2.0
88/342
CD-adapco, Americas Agency Training Document CFD Basics - 88
CFD Basics : Post-Processing - Isosurfaces
7/23/2019 Lec STARCCM FoundationTrainingV2.0
89/342
CD-adapco, Americas Agency Training Document CFD Basics - 89
TotalPressure=0,Isosurface
plot.
CFD Basics - Divergence
7/23/2019 Lec STARCCM FoundationTrainingV2.0
90/342
CD-adapco, Americas Agency Training Document CFD Basics - 90
What do I do if my solution diverges?
- Check physical models chosen, and boundary conditionsapplied.
- Check and make sure dimensions of the problem are setupcorrectly.
- Check and make sure mesh quality is good, and sufficient
mesh density is available for resolving the flow features.- Reduce under-relaxation factors.
- Simplify the physics
CFD Basics Ensuring Quality in CFD Analysis
7/23/2019 Lec STARCCM FoundationTrainingV2.0
91/342
CD-adapco, Americas Agency Training Document CFD Basics - 91
Ensuring quality of CFD analysis is an important process.The next few slides briefly outline practices used withinCD-adapco.
CFD Basics Ensuring Quality in CFD Analysis
7/23/2019 Lec STARCCM FoundationTrainingV2.0
92/342
CD-adapco, Americas Agency Training Document CFD Basics - 92
Main Phases:
1. Initial Project Review
2. Pre-Analysis Review
3. Final Analysis Review
CFD Basics Ensuring Quality of CFD Analysis
7/23/2019 Lec STARCCM FoundationTrainingV2.0
93/342
CD-adapco, Americas Agency Training Document CFD Basics - 93
Initial Project Review
- Define scope of project and cross check with customer
- Define time frame and resources for project
- Check with customer and make sure all cad data isavailable and consistent
CFD Basics Ensuring Quality of CFD Analysis
7/23/2019 Lec STARCCM FoundationTrainingV2.0
94/342
CD-adapco, Americas Agency Training Document CFD Basics - 94
Pre Analysis Review
- Does the generated mesh match CAD supplied?
- Have the boundary conditions been correctly applied?
- Is the mesh density sufficient to answer objectives ofanalysis?
- Have correct material properties been defined?
- Have the correct physics models been applied?
- What post processing is required?
- Do results from running a few iterations / time steps look
reasonable?
CFD Basics Ensuring Quality of CFD Analysis
7/23/2019 Lec STARCCM FoundationTrainingV2.0
95/342
CD-adapco, Americas Agency Training Document CFD Basics - 95
Final Analysis Review
- Has the solution fully converged?
- Double check, initial and boundary conditions
- Double check material properties
- Do results make physical sense? (compare with prioranalysis if possible)
- Have all the questions of the customer been answered?
CFD Basics: CD-adapco Solvers
7/23/2019 Lec STARCCM FoundationTrainingV2.0
96/342
CD-adapco, Americas Agency Training Document CFD Basics - 96
CD-adapco offers two CFD Solvers:
STAR-CD
- V3.2x- 20 Years of Development
- V4.x
- Rewrite of STAR V3.2x as a face based solver.
- Uses an upgraded pre/post Processor of V3.2x
STAR-CCM+
- New Integrated Meshing / Pre-Processor / Solver / Post Processor, allunder one GUI.
- Developed with novel concepts, keeping in mind of very large models.
CFD Basics Comparison of CD-adapco Solvers
7/23/2019 Lec STARCCM FoundationTrainingV2.0
97/342
CD-adapco, Americas Agency Training Document CFD Basics - 97
The next few slides compare the available features (formesh generation, physics, and coupling) in STAR V3.26,STAR V4.06 and STAR-CCM+ V3.02
CFD Basics Comparison of Solvers Mesh Topology
7/23/2019 Lec STARCCM FoundationTrainingV2.0
98/342
CD-adapco, Americas Agency Training Document CFD Basics - 98
YesYesNoArbirtraryPolyhedra
YesYesYesHex / Tet (Hybrid)
YesYesYesHexahedral / Trim
YesYesYesHexahedral
STAR-CCM+
V3.02
STAR-CD V4.06STAR-CD V3.26Mesh Type
CFD Basics Comparison of Solvers Mesh Motion
7/23/2019 Lec STARCCM FoundationTrainingV2.0
99/342
CD-adapco, Americas Agency Training Document CFD Basics - 99
NoYesYesCell layer addition /removal
NoYesYesConditional Cellattachment / detachment
NoYesYesGeneral Mesh Motion
YesNoNoParallel Partition across
interfaces
YesYesYesArbitrary Sliding Meshes
YesYesYesRotating ReferenceFrames
STAR-CCM+V3.02
STAR-CDV4.06
STAR-CDV3.26
Mesh Motion
CFD Basics Comparison of Solvers SolutionAlgorithms
7/23/2019 Lec STARCCM FoundationTrainingV2.0
100/342
CD-adapco, Americas Agency Training Document CFD Basics - 100
YesNoNoCoupled Solver
NoYesYesPISO
YesYesYesAMG
YesYesYes*SIMPLE
STAR-CCM+
V3.02
STAR-CD V4.06STAR-CD V3.26Algorithm
Note:Note:Note:Note: STARV3.26hasSIMPLEforSteadyStateOnly.
CFD Basics Comparison of Solvers Heat Transfer
7/23/2019 Lec STARCCM FoundationTrainingV2.0
101/342
CD-adapco, Americas Agency Training Document CFD Basics - 101
YesYesYesSolar Radiation
YesYesYesTransparent Solids
YesYesYesParticipating Media
Radiation
YesYesYesSurface ExchangeRadiation
YesYesYesConjugate Heat Transfer
STAR-CCM+V3.02
STAR-CDV4.06
STAR-CDV3.26
Heat Transfer
CFD Basics Comparison of Solvers GeneralCombustion Models
STAR-CCM+STAR-CDSTAR-CDMesh Type
7/23/2019 Lec STARCCM FoundationTrainingV2.0
102/342
CD-adapco, Americas Agency Training Document CFD Basics - 102
NoYesYesNOx and SOOT Models
NoYesYesHybrid (kinetic / EBU)
YesYesYesPPDF
YesYesYesIgnition
NoYesYesComplex Chemistry
YesYesYesEBU
YesYesYesCFM
YesYesYesGaseous
NoYesYesLiquid
NoYesYesSolid (e.g. Coal)V3.02V4.06V3.26
yp
CFD Basics Comparison of Solvers IC EngineCombustion Models
7/23/2019 Lec STARCCM FoundationTrainingV2.0
103/342
CD-adapco, Americas Agency Training Document CFD Basics - 103
NoYesYesNOx
NoYesYesSOOT
NoYesYesDiesel Ignition Models
NoYesYesEGR
NoYesYesDiesel Combustion Models
NoYesYesPartially Premixed SI
NoYesYesPremixed SI
STAR-CCM+V3.02
STAR-CDV4.06
STAR-CDV3.26
IC Engine Combustion
CFD Basics Comparison of Solvers Multi-PhaseFlows
7/23/2019 Lec STARCCM FoundationTrainingV2.0
104/342
CD-adapco, Americas Agency Training Document CFD Basics - 104
NoYesYesInterpenetratingPhases (Eulerian)
NoYesYesLiquid Film
Yes*YesYesDispersed Multiphase(Lagrangian)
YesYesYesCavitation
YesYesYesFree Surface
STAR-CCM+
V3.02
STAR-CD V4.06STAR-CD V3.26Feature
Note:* Currently L2P in STAR-CCM+ does not include evaporation.
CFD Basics Comparison of Solvers Multiphysics
7/23/2019 Lec STARCCM FoundationTrainingV2.0
105/342
CD-adapco, Americas Agency Training Document CFD Basics - 105
NoYes* (Beta)NoMelting andSolidification
NoYes* (Beta)NoElectromagnetics
NoYes* (Beta)NoStress
NoNoYesFluid StructureInteraction
YesYesYesAeroacoustics
STAR-CCM+
V3.02
STAR-CD V4.06STAR-CD V3.26Feature
CFD Basics Comparison of Solvers Coupling to OtherCodes
STAR CCMSTAR CD V4 06STAR CD V3 26CODE
7/23/2019 Lec STARCCM FoundationTrainingV2.0
106/342
CD-adapco, Americas Agency Training Document CFD Basics - 106
NoNoYesCHEMKIN
NoYesYesSYSNOISE andACTRAN
YesYesYes* (V3.27)DARS
NoYesYesFlowMaster
NoYesYesWave
NoYesYesGT-Power
STAR-CCM+V3.02
STAR-CD V4.06STAR-CD V3.26CODE
7/23/2019 Lec STARCCM FoundationTrainingV2.0
107/342
7/23/2019 Lec STARCCM FoundationTrainingV2.0
108/342
Lecture STAR-CCM+ - Basics
This lecture introduces the basics of STAR-CCM+ to a new user.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
109/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -1
Topics Covered
1. Introduction to the client server architecture2. Unique features
3. Meshing capabilities
4. Physics Models
5. Boundary conditions and Post-Processing
6. GUI layout
7. Simulation File
8. Workflow
9. Accessing Help
Lecture - STAR-CCM+ Basics - Introduction
7/23/2019 Lec STARCCM FoundationTrainingV2.0
110/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -2
STAR-CCM+ is a state-of-the-art CFD solver from CD-adapco that uses a Client Server approach.
- Java front end(light on memory) and a C++ server
ClientClientClientClient
ServerServerServerServer
Lecture - STAR-CCM+ Basics - Introduction
What is a client?
7/23/2019 Lec STARCCM FoundationTrainingV2.0
111/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -3
Client is the part through which you launch a simulationand work with, typically through the STAR-CCM+
workspace.
What is a server?
Server is the part of the architecture that implementscommands in a simulation (e.g. import data, run the solver)
Lecture - STAR-CCM+ - Basics Unique Environment
What is unique about the STAR CCM+ environment?
7/23/2019 Lec STARCCM FoundationTrainingV2.0
112/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -4
What is unique about the STAR-CCM+ environment? State of the art object-based GUI
Simulation database:
Fast, loaded on demand Binary Platform and Parallel independent
User Programming
Java language scripting
User defined boundary conditions, source terms and post-processing Scalable, seamless parallel operation
Client Server Architecture Operable on Windows, LINUX, and several UNIX platforms
Documentation
Via online browser Context Sensitive help with F1 Key pdf document
Lecture - STAR-CCM+ Basics Novel Concepts
1. Multi-Physics, continuum based modeling.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
113/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -5
2. Separation of Physics and Mesh.
3. Generalized interfaces (allow communication between
different regions in the solution domain).
Lecture - STAR-CCM+ Basics Ports Supported
STAR-CCM+ is currently ported to:
7/23/2019 Lec STARCCM FoundationTrainingV2.0
114/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -6
Windows 2000 / XP (32 bit and 64 bit)
Linux 32 bit
Linux 64 bit
IBM AIX
HPUX PaRisc
HP Itanium
SGI Altix
Sun Solaris
Lecture - STAR-CCM+ Basics Mesh
7/23/2019 Lec STARCCM FoundationTrainingV2.0
115/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -7
Surface Mesh Formats
.dbs pro-STAR surface database
.inp pro-STAR cell / vertex shell input file
.nas NASTRAN shell file
.pat PATRAN shell file
.stl Stereolithography file .fro FELISA front surface file
Jt JT Open Surface file
Lecture STAR-CCM+ Basics - Mesh
CAD Import Formats
7/23/2019 Lec STARCCM FoundationTrainingV2.0
116/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -8
- x_t, x_b Parasolid Transmit File
- .stp, .step Standardized Exchange of Product File
- .igs, .iges International Graphics Exchange Standard File
Lecture - STAR-CCM+ - Basics - Mesh
Surface Meshing
Surface Remesher
7/23/2019 Lec STARCCM FoundationTrainingV2.0
117/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -9
Surface Remesher
Surface Wrapper (automated method for closing surfaces)
Hole Filling
Rough Patcher
Edge Zipper
Edge split, swap (techniques for improving triangle quality)
Automatic repair of surface errors
Automatic / Manual extraction of feature curves
Surface Creation and Manipulation
- Creation of simple shapes
- Boolean Unite, Subtract and Intersect
Lecture STAR-CCM+ Basics - Mesh
Volume Meshing
Core Mesh
7/23/2019 Lec STARCCM FoundationTrainingV2.0
118/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -10
Core Mesh
Tetrahedral mesh
Polyhedral mesh
Advanced Hexahedral (Trim) mesh
Boundary Layer mesh with prism layer
Local / global parameter setting for mesh generation
Volume sources (shapes like box, cone, cylinder, sphere fordeclaring regions in the cfd domain that need refinement)
Extruder (For extending domains, building a solid layer)
Lecture - STAR-CCM+ Basics - Mesh
Mesh Manipulation
T f l l d fl h
7/23/2019 Lec STARCCM FoundationTrainingV2.0
119/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -11
Transform scale, translate, rotate, and reflect meshes
Split and combine boundaries and regions
Create, delete and fuse interfaces
Convert 3D mesh to 2D mesh
Create Cell Sets
Lecture - STAR-CCM+ - Basics - Mesh
Import of Volume Mesh
STAR
7/23/2019 Lec STARCCM FoundationTrainingV2.0
120/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -12
pro-STAR
Gridgen (via .cas file)
Fluent (.cas, .msh)
Gambit
ICEM
Lecture - STAR-CCM+ Basics - Physics
Basic Models
7/23/2019 Lec STARCCM FoundationTrainingV2.0
121/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -13
Space
Two-Dimensional Axisymmetric
Three-Dimensional
Time
Steady
Explicit / Implicit Unsteady
Motion
Moving Reference Frames, Rotational, Translational Frozen Rotor (multiple reference frame)
Lecture - STAR-CCM+ Basics - Physics
Flow and Energy
7/23/2019 Lec STARCCM FoundationTrainingV2.0
122/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -14
Inviscid, Laminar and Turbulent flow regimes
Gas, Liquid, Solid, and Porous Media Total Energy Formulation
Conjugate Heat Transfer
Free-surface (VOF) Cavitation
Lagrangian Multi-phase (no evaporation)
Radiator Type Heat Exchanger
Fan Curve Adjusted Momentum Source Fan
Lecture - STAR-CCM+ Basics - Physics
Turbulence Models
7/23/2019 Lec STARCCM FoundationTrainingV2.0
123/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -15
3 Variants of Spallart-Allmaras
7 Variants of k-
3 Variants of k-
3 Variants of Reynolds Stress Transport
Large Eddy Simulation
Detached Eddy Simulation Wall Treatment
Low y+
High y+
All y+
Lecture - STAR-CCM+ Basics - Physics
Radiation
7/23/2019 Lec STARCCM FoundationTrainingV2.0
124/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -16
Thermal
Solar
View Factors including support for baffles and symmetric boundaries
Surface-to-Surface
Participating Media
Multiphase Flow
VOF
Cavitation
Homogeneous Boiling Model
Lagrangian Multi-Phase
Lecture - STAR-CCM+ Basics - Physics
Combustion
7/23/2019 Lec STARCCM FoundationTrainingV2.0
125/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -17
Eddy Break Up (EBU)
Coherent Flame (CFM)
Partially-Premixed Coherent Flame (PCFM)
Presumed Probability Density Function (PPDF), adiabatic
and non-adiabatic Ignitors
Lecture - STAR-CCM+ Basics Boundary Conditions
Boundary Conditions
7/23/2019 Lec STARCCM FoundationTrainingV2.0
126/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -18
Wall
No-slip, slip, specified temperature, adiabatic, specified heat flux,
thermally convective wall (Tamb and heat transfer coefficient specified)
Pressure Outlet
Specified pressure, radial equilibrium
Flow Split Outlet
Specified outlet mass flow for incompressible flows Mass Flow Inlet
Specified mass flow for compressible flows
Stagnation Inlet
Total Temperature, Total Pressure and Flow Direction
Lecture - STAR-CCM+ Basics Boundary Conditions
Non-Reflecting
Average total pressure, temperature and flow angle at inlet, static
7/23/2019 Lec STARCCM FoundationTrainingV2.0
127/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -19
g p p gpressure at outlet.
Velocity Inlet
Specified velocity components, or specified magnitude anddirection
Free Stream
Specified Mach number and flow angle, static temperature andstatic pressure
Symmetry Plane
Axis
For Axisymmetric simulations
Lecture - STAR-CCM+ Basics - Numerics
Numerics in STAR-CCM+
7/23/2019 Lec STARCCM FoundationTrainingV2.0
128/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -20
1. Segregated Implicit Uses AMG SIMPLE solver
2. Coupled Explicit Uses multi-stage Runge-Kutta solver
3. Coupled Implicit Uses block AMG solver
Lecture - STAR-CCM+ Basics Tools for Interacting withthe Solution
What are the tools available for interacting with thesolution?
7/23/2019 Lec STARCCM FoundationTrainingV2.0
129/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -21
- User defined properties and conditions
- Local coordinate systems
- Engineering Units for Input and Output (SI, USCS, User
defined)- Full interactivity between user and solution
- Field Functions
- Reports and Monitors- Derived Parts (iso-surfaces, planes, lines, points, etc.)
Lecture - STAR-CCM+ Basics Tools For Interacting withthe Solution
- Visualization
- Mesh, scalar and vector display
7/23/2019 Lec STARCCM FoundationTrainingV2.0
130/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -22
, p y
- Streamlines
- Animated streamlines and vectors- Transforms (for symmetric or periodic models)
- Annotations with text or images
- Scene Legend- Save Restore Views
- High Resolution hard copy for plots
- X-Y plotting capability
Lecture - STAR-CCM+ Basics - Terminology
STAR-CCM+ uses thefollowing terminology:
R i
7/23/2019 Lec STARCCM FoundationTrainingV2.0
131/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -23
1. Regions
2. Boundaries
3. Interfaces
4. Continuum
Using the example shown onthe right, the next few slidesexplain the terminology used.
Lecture - STAR-CCM+ Basics - Region
A Region is a volume domain in space. Could be conformal (nodes
connected one to one) or non-conformal (nodes not connected one to one).
7/23/2019 Lec STARCCM FoundationTrainingV2.0
132/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -24
Lecture - STAR-CCM+ Basics - Boundaries
Boundariesare the exterior surface of regions. They could be aphysical boundary (e.g. wall, inlet, outlet) or a connectionbetween different regions
7/23/2019 Lec STARCCM FoundationTrainingV2.0
133/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -25
between different regions.
Lecture - STAR-CCM+ Basics - Interfaces
Interfacespermit transfer of mass and (or) energy between differentregions, or non-conformal parts of the same region.
Internal interface permits transfer of mass and energy
7/23/2019 Lec STARCCM FoundationTrainingV2.0
134/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -26
Internal interface permits transfer of mass and energy.
Contact interface permits transfer of energy only.
Lecture - STAR-CCM+ Basics - Continuum
A continuumrepresents a collection of models that represent eitherthe physics or the mesh of a given region.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
135/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -27
Lecture - STAR-CCM+ Basics Mouse Controls
Left Rotate
Middle Zoom
Right P
7/23/2019 Lec STARCCM FoundationTrainingV2.0
136/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -28
Right Pan
Shift + Left Zoom box
Lecture - STAR-CCM+ Basics Launching STAR-CCM+
In Windows:
Double click on the STAR-CCM+ Icon
7/23/2019 Lec STARCCM FoundationTrainingV2.0
137/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -29
In UNIX/LINUX
Issue the command starccm+
Note: Need to make sure that the location of the starccm+
executable is defined in the path environmental variable.
Lecture - STAR-CCM+ Basics - Startup
At startup, user can either:
1. Start a new simulation.
2 Load an existing simulation
7/23/2019 Lec STARCCM FoundationTrainingV2.0
138/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -30
2. Load an existing simulation(after browsing files).
3. Select a simulation fromrecently opened simulations.
Lecture - STAR-CCM+ Basics - Workspace
7/23/2019 Lec STARCCM FoundationTrainingV2.0
139/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -31
Lecture STAR-CCM+ Basics - Toolbars
Toolbars in STAR-CCM+ provide easy access to commontasks executed while preparing and running a simulation.The next slide shows standard toolbars in STAR CCM+
7/23/2019 Lec STARCCM FoundationTrainingV2.0
140/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -32
The next slide shows standard toolbars in STAR-CCM+.
STAR-CCM+ provides methods for controlling theappearance of toolbars.
Lecture - STAR-CCM+ Basics - Toolbars
EditToolbar
SystemToolbar
7/23/2019 Lec STARCCM FoundationTrainingV2.0
141/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -33
MeshToolbar
DataToolbar
DisplayToolbar
BuildToolbar
PlotToolbar
AnimateToolbar
Lecture - STAR-CCM+ - Objects
7/23/2019 Lec STARCCM FoundationTrainingV2.0
142/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -34
7/23/2019 Lec STARCCM FoundationTrainingV2.0
143/342
Lecture - STAR-CCM+ Basics - GeneralInformation
STAR-CCM+ has one file: (.sim)that contains the mesh, analysissetup and results.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
144/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -36
How do I save the simulation?
File -> Save
Lecture - STAR-CCM+ Basics: GeneralInformation
How do I run a simulation?
Either:
1. Solution -> Run
7/23/2019 Lec STARCCM FoundationTrainingV2.0
145/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -37
2. Toolbar, pick run icon
Lecture - STAR-CCM+ Basics SettingPreferences
7/23/2019 Lec STARCCM FoundationTrainingV2.0
146/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -38
Lecture - STAR-CCM+ Basics SettingPreferences
7/23/2019 Lec STARCCM FoundationTrainingV2.0
147/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -39
Lecture - STAR-CCM+ - General Information Work Flow
Work Flow in STAR-CCM+
Import CAD
7/23/2019 Lec STARCCM FoundationTrainingV2.0
148/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -40
Check Surface
Do manual repair if required.
Setup Meshing Models and properties
Setup Physics Models and properties
Setup Boundary Conditions Generate Mesh
Setup solver parameters and stopping criteria
Setup post-processing (optional)
Run analysis
Lecture - STAR-CCM+ - General Information - Workflow
7/23/2019 Lec STARCCM FoundationTrainingV2.0
149/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -41
Lecture - STAR-CCM+ - Getting Help
If you need help, you can clickon the help button.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
150/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -42
Lecture - STAR-CCM+ - Getting Help
The online documentation can be accessed with a browser
7/23/2019 Lec STARCCM FoundationTrainingV2.0
151/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -43
Lecture STAR-CCM+ - Basics - Help
Help contains:
Model description and formulation.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
152/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -44
Model description and formulation.
Meshing, Solving, and Post-Processing techniques
GUI panel descriptions.
Training Guide that has several tutorials
Lecture - STAR-CCM+ - Getting Help
In addition the F1 Key providescontext sensitive help.
e g If you need help on
7/23/2019 Lec STARCCM FoundationTrainingV2.0
153/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -45
e.g. If you need help on
stopping criteria, then selectStopping Criteria, and hit the F1key.
Lecture - STAR-CCM+ - Getting Help
The browser will display help on Stopping Criteria
7/23/2019 Lec STARCCM FoundationTrainingV2.0
154/342
CD-adapco, Americas Agency Training Document STAR-CCM+ Basics -46
7/23/2019 Lec STARCCM FoundationTrainingV2.0
155/342
7/23/2019 Lec STARCCM FoundationTrainingV2.0
156/342
Lecture - STAR-CCM+ - Post-Processing
This section covers basic post-processing techniques instarccm+. For this case, we will use a pre-existingsimulation file (lock30.sim).
7/23/2019 Lec STARCCM FoundationTrainingV2.0
157/342
CD-adapco, Americas Agency Training Document Post-Processing - 1
Main topics covered
1. Scene Properties
2.
Working with Views3. Creation of Iso-surface
4. Creation of tables to extract boundary values
5. XY Plotting
Lecture - STAR-CCM+ - Post-Processing Location offile
File for the exercise (lock30.sim) is located in:
7/23/2019 Lec STARCCM FoundationTrainingV2.0
158/342
CD-adapco, Americas Agency Training Document Post-Processing - 2
Foundation/STARCCM+/PostProcessing
Lecture - STAR-CCM+ - Post-Processing - Basics
STAR-CCM+ provides a powerful set of tools to visualizeyour solution.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
159/342
CD-adapco, Americas Agency Training Document Post-Processing - 3
Post-Processing can be setup before, or after a CFDsolution is obtained.
Setting up of post-processing before start of the CFDsolution, offers the advantage of watching the solutiondevelop (as the CFD analysis is running in serial or parallelmode)
Lecture - Post-Processing - Basics
What is a Scene?A scene encapsulates a complete representation ofcomponents required to create an image or animation. Itincludes lights, cameras, actors, properties,
7/23/2019 Lec STARCCM FoundationTrainingV2.0
160/342
CD-adapco, Americas Agency Training Document Post-Processing - 4
includes lights, cameras, actors, properties,
transformations and geometry.
What are the various types of Scenes?
GeometrySceneMeshScene
ScalarScene
VectorScene
EmptyScene
Lecture - Post-Processing - Displayers
What is a displayer?
It is the basic building block of a scene. Displayers providea flexible way of controlling graphics entities in a scene.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
161/342
CD-adapco, Americas Agency Training Document Post-Processing - 5
What are the types of displayers available?
Geometrydisplayer (controls geometric appearance)
Outlinedisplayer (controls appearance of sharp edges)Scalardisplayer (controls appearance of scalar contours)
Vectordisplayer (controls appearance of vectors)
Streamlinedisplayer (controls appearance of streamlines)
Lecture - Post-Processing - Displayers
The next few slides show the layout of a typical scene inSTAR-CCM+ (taken from our lock-valve tutorial) that has ageometryand scalardisplayer.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
162/342
CD-adapco, Americas Agency Training Document Post-Processing - 6
The properties associated with these displayers areexplained.
Lecture - Post-Processing - Displayers
WhataretheAttributesofaScene?WhataretheAttributesofaScene?WhataretheAttributesofaScene?WhataretheAttributesofaScene?
-Backgroundcolor
-View(Projectionmode)
7/23/2019 Lec STARCCM FoundationTrainingV2.0
163/342
CD-adapco, Americas Agency Training Document Post-Processing - 7
-Update(Isplotupdatedperiteration,timestep?Whereisit
output(screenorfile))
-Axes(Istriaddisplayed?)
-Lights
Lecture - Post-Processing - Displayers
Geometry displayercontrols
-Color Mode
7/23/2019 Lec STARCCM FoundationTrainingV2.0
164/342
CD-adapco, Americas Agency Training Document Post-Processing - 8
-Opacity
- Representation shown
-Display of outline, mesh
-Lighting
-Transforms
Lecture - Post-Processing - Displayers
Properties of Outlinedisplayer are similar to thegeometry displayer, but itcontrols the appearance of
7/23/2019 Lec STARCCM FoundationTrainingV2.0
165/342
CD-adapco, Americas Agency Training Document Post-Processing - 9
outlines (edges) in the plot.
Lecture - Post-Processing - Displayers
Properties of a contourplot are controlled bythe Scalar Displayer.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
166/342
CD-adapco, Americas Agency Training Document Post-Processing - 10
Lecture Post-Processing - Displayers
7/23/2019 Lec STARCCM FoundationTrainingV2.0
167/342
CD-adapco, Americas Agency Training Document Post-Processing - 11
Lecture Post-Processing - Displayers
Main properties vector displayercontrols:
-Vector appearance and style
7/23/2019 Lec STARCCM FoundationTrainingV2.0
168/342
CD-adapco, Americas Agency Training Document Post-Processing - 12
-Projection mode-Opacity
-Lighting
7/23/2019 Lec STARCCM FoundationTrainingV2.0
169/342
Lecture Post-Processing - Views
Views control the appearance of a plot in STAR-CCM+.
What are the three attributes of a view?
7/23/2019 Lec STARCCM FoundationTrainingV2.0
170/342
CD-adapco, Americas Agency Training Document Post-Processing - 14
- Position- Focal Point
- View up
- Projection Mode
Where can I access views?
Via Tools Folder
Lecture Post-Processing - Views
7/23/2019 Lec STARCCM FoundationTrainingV2.0
171/342
CD-adapco, Americas Agency Training Document Post-Processing - 15
Lecture Post-Processing - Views
What is the Projection Mode?Property that controls how the camera maps worldcoordinates to view coordinates.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
172/342
CD-adapco, Americas Agency Training Document Post-Processing - 16
Perspective Mapping of world coordinates into viewcoordinates that roughly approximates a camera lens.
Parallel Mapping of world coordinates into viewcoordinates that preserves all parallel lines.
Lecture Post-Processing - Views
How can I access standard views?
7/23/2019 Lec STARCCM FoundationTrainingV2.0
173/342
CD-adapco, Americas Agency Training Document Post-Processing - 17
Lecture Post-Processing Iso-surfaces
Iso-surfaces can be created via the Derived Parts folder inSTAR-CCM+.
O t d i f b di l d i g m t
7/23/2019 Lec STARCCM FoundationTrainingV2.0
174/342
CD-adapco, Americas Agency Training Document Post-Processing - 18
Once created, iso-surfaces can be displayed in geometry,scalar and vector scenes, by including it in the parts folderof the appropriate geometry.
Exercise: Create an iso-surface of turbulent viscosity ratio= 20 for the lock valve 30 deg Configuration.
Lecture Post-Processing Iso-surface
7/23/2019 Lec STARCCM FoundationTrainingV2.0
175/342
CD-adapco, Americas Agency Training Document Post-Processing - 19
Lecture Post-Processing Iso-Surfaces
7/23/2019 Lec STARCCM FoundationTrainingV2.0
176/342
CD-adapco, Americas Agency Training Document Post-Processing - 20
Lecture Post-Processing Iso-Surface
7/23/2019 Lec STARCCM FoundationTrainingV2.0
177/342
CD-adapco, Americas Agency Training Document Post-Processing - 21
7/23/2019 Lec STARCCM FoundationTrainingV2.0
178/342
Lecture Post-Processing - Tables
7/23/2019 Lec STARCCM FoundationTrainingV2.0
179/342
CD-adapco, Americas Agency Training Document Post-Processing - 23
Lecture Post-Processing - Tables
7/23/2019 Lec STARCCM FoundationTrainingV2.0
180/342
CD-adapco, Americas Agency Training Document Post-Processing - 24
Lecture Post-Processing - Tables
7/23/2019 Lec STARCCM FoundationTrainingV2.0
181/342
CD-adapco, Americas Agency Training Document Post-Processing - 25
Lecture Post-Processing XY Plots
The next few slides outline a procedure for creation of aline probe along a plane section, and plotting pressure onthis line probe in the form of an XY plot.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
182/342
CD-adapco, Americas Agency Training Document Post-Processing - 26
7/23/2019 Lec STARCCM FoundationTrainingV2.0
183/342
Lecture Post-Processing XY plot
7/23/2019 Lec STARCCM FoundationTrainingV2.0
184/342
CD-adapco, Americas Agency Training Document Post-Processing - 28
Lecture Post-Processing XY plot
7/23/2019 Lec STARCCM FoundationTrainingV2.0
185/342
CD-adapco, Americas Agency Training Document Post-Processing - 29
Lecture Post-Processing XY Plot
7/23/2019 Lec STARCCM FoundationTrainingV2.0
186/342
CD-adapco, Americas Agency Training Document Post-Processing - 30
Lecture Post-Processing XY Plot
7/23/2019 Lec STARCCM FoundationTrainingV2.0
187/342
CD-adapco, Americas Agency Training Document Post-Processing - 31
Lecture Post-Processing XY Plot
7/23/2019 Lec STARCCM FoundationTrainingV2.0
188/342
CD-adapco, Americas Agency Training Document Post-Processing - 32
Lecture Post-Processing XY Plot
7/23/2019 Lec STARCCM FoundationTrainingV2.0
189/342
CD-adapco, Americas Agency Training Document Post-Processing - 33
7/23/2019 Lec STARCCM FoundationTrainingV2.0
190/342
7/23/2019 Lec STARCCM FoundationTrainingV2.0
191/342
7/23/2019 Lec STARCCM FoundationTrainingV2.0
192/342
Lecture - STAR-CCM+ - Meshing
This Lecture outlines the Mesh Generation capabilitiesthat are currently available in STAR-CCM+.
Topics1. Surface Mesh Import and Checks
7/23/2019 Lec STARCCM FoundationTrainingV2.0
193/342
CD-adapco, Americas Agency Training Document Meshing -1
1. Surface Mesh Import and Checks
2. Surface Mesh fixing tools
3. Mesh generation Models
4. Mesh Model Parameters
5. Volume mesh generation
6. Cell Quality Metrics
Lecture - STAR-CCM+ - Meshing SurfaceImport
What are the surface mesh formats allowed by STAR-CCM+?
.dbs proSTAR/amm database file
.inp proSTAR/amm cell, vertex file
NASTRAN h ll fil
7/23/2019 Lec STARCCM FoundationTrainingV2.0
194/342
CD-adapco, Americas Agency Training Document Meshing -2
.nas NASTRAN shell file
.pat PATRAN shell file
.stl Stereolithography file
.fro- FELISA front surface file
.jt JT Open Surface file
Lecture - STAR-CCM+ - Meshing SurfaceImport Format Summary
7/23/2019 Lec STARCCM FoundationTrainingV2.0
195/342
CD-adapco, Americas Agency Training Document Meshing -3
7/23/2019 Lec STARCCM FoundationTrainingV2.0
196/342
Lecture STAR-CCM+ Meshing CAD Import FormatSummary
7/23/2019 Lec STARCCM FoundationTrainingV2.0
197/342
CD-adapco, Americas Agency Training Document Meshing -5
Lecture - STAR-CCM+ - Meshing Surface Requirement
What are the requirements for a surface mesh?
Closed No free edges or mismatches
Manifold Edges shared by no more than two trianglesNon-Intersecting surface does not self intersect
7/23/2019 Lec STARCCM FoundationTrainingV2.0
198/342
CD-adapco, Americas Agency Training Document Meshing -6
g
Good triangle quality- Nearly equal sized triangles
- Gradual variation in triangle size
- No sharp angles/ surface folds
Lecture - STAR-CCM+ - Meshing SurfaceFixing
What are the errors that can be fixed in STAR-CCM+?Holes
Mismatchesin surface (shells not connected one to one)
Double surfaces, overlapsand unwanted internalfeatures(via surface wrap)
7/23/2019 Lec STARCCM FoundationTrainingV2.0
199/342
CD-adapco, Americas Agency Training Document Meshing -7
Pierced edges(self intersections)
Details of surface repair in STAR-CCM+ will be coveredwith a tutorial.
Lecture - STAR-CCM+ - Meshing Surface Checking
How can I check the imported surface for errors?
1. Open RepresentationsFolder.
2. Right click on Import, and select Repair Surface.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
200/342
CD-adapco, Americas Agency Training Document Meshing -8
Lecture STAR-CCM+ Meshing Surface Fixing
7/23/2019 Lec STARCCM FoundationTrainingV2.0
201/342
CD-adapco, Americas Agency Training Document Meshing -9
Lecture STAR-CCM+ Meshing Surface Checks
7/23/2019 Lec STARCCM FoundationTrainingV2.0
202/342
CD-adapco, Americas Agency Training Document Meshing -10
Lecture STAR-CCM+ Meshing Surface Repair
- After running surface checks, review the errors in surface.- If there are too may errors to fix, you may need to run
surface wrapper to fix errors.
- If there are a few errors in the surface, the followingprocedure is recommended:
7/23/2019 Lec STARCCM FoundationTrainingV2.0
203/342
CD-adapco, Americas Agency Training Document Meshing -11
1. Fix non-manifold errors and free edges.
2. Run Auto-repair to fix remaining errors
Lecture STAR-CCM+ Meshing Surface Repair -Options
7/23/2019 Lec STARCCM FoundationTrainingV2.0
204/342
CD-adapco, Americas Agency Training Document Meshing -12
Lecture STAR-CCM+ Meshing Surface Repair -Options
7/23/2019 Lec STARCCM FoundationTrainingV2.0
205/342
CD-adapco, Americas Agency Training Document Meshing -13
Lecture STAR-CCM+ Meshing Surface Repair Selection Controls
7/23/2019 Lec STARCCM FoundationTrainingV2.0
206/342
CD-adapco, Americas Agency Training Document Meshing -14
Lecture STAR-CCM+ Meshing Surface Repair Display Controls
7/23/2019 Lec STARCCM FoundationTrainingV2.0
207/342
CD-adapco, Americas Agency Training Document Meshing -15
Lecture - STAR-CCM+ - Meshing - Continuum
What is a mesh continuum?A mesh continuum is a collection of models that are usedto generate a mesh.
What are the models that are available?Surface Wrapper
7/23/2019 Lec STARCCM FoundationTrainingV2.0
208/342
CD-adapco, Americas Agency Training Document Meshing -16
pp
Remesher
Volume Mesher (tetrahedral, trimmed, polyhedral)Prism Layer Mesher
Extruder
Lecture STAR-CCM+ Meshing Surface MesherSelection
When should the surface remesherbe used?
- When a high accuracy of surface resolution is required.
- When imported surface is closed, but has poor qualitytriangulation (e.g. STL import)
When triangulation quality of import surface has to be
7/23/2019 Lec STARCCM FoundationTrainingV2.0
209/342
CD-adapco, Americas Agency Training Document Meshing -17
- When triangulation quality of import surface has to beimproved.
- When surface wrapper has been used.
Lecture STAR-CCM+ Meshing - Surface Mesher Choice
When should the Surface Wrapperbe used?- When a high level of surface accuracy is not critical
- When imported surface contains large gaps, holes andoverlaps that cannot be fixed easily using manual repair.
- When import surface is made up of intersecting volumesthat have to be combined
7/23/2019 Lec STARCCM FoundationTrainingV2.0
210/342
CD-adapco, Americas Agency Training Document Meshing -18
that have to be combined.
Lecture - STAR-CCM+ - Meshing ModelSelection
To select models, right click onMesh Continuum
Pick Select Meshing Models
7/23/2019 Lec STARCCM FoundationTrainingV2.0
211/342
CD-adapco, Americas Agency Training Document Meshing -19
7/23/2019 Lec STARCCM FoundationTrainingV2.0
212/342
Lecture - STAR-CCM+ - Meshing Reference Values
The properties of the Meshingmodels can be specified viathe Reference ValuesFolder
7/23/2019 Lec STARCCM FoundationTrainingV2.0
213/342
CD-adapco, Americas Agency Training Document Meshing -21
Lecture - STAR-CCM+ - Meshing Reference Values
Reference values allowed, depend on meshing models selected.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
214/342
CD-adapco, Americas Agency Training Document Meshing -22
Lecture - STAR-CCM+ - Meshing Reference Values
Reference values can be specified at 4 levels:1. Continuum
2. Region
3.
Boundary4. Interface
7/23/2019 Lec STARCCM FoundationTrainingV2.0
215/342
CD-adapco, Americas Agency Training Document Meshing -23
Values specified at the boundary and interface levelsupercede values specified at region level, which in turnsupercedes values specified at a continuum level.
Lecture - STAR-CCM+ - Meshing Reference ValueSpecification
What is the base size?Base size refers to a characteristic size used in meshgeneration.
What is a target size?
Desired edge length
7/23/2019 Lec STARCCM FoundationTrainingV2.0
216/342
CD-adapco, Americas Agency Training Document Meshing -24
es ed edge e gt
What do we mean by min-max size?
When proximity / curvature refinements are turned on, thisparameter controls the lower and upper bounds of the cell
size.
Lecture - STAR-CCM+ - Meshing Reference ValueSpecification
Methods for specifying surface size:
Min and Target
-Try to achieve target size in absence of refinement from
curvature / proximity-Refinements from curvature will not cause surface size togo below minimum
7/23/2019 Lec STARCCM FoundationTrainingV2.0
217/342
CD-adapco, Americas Agency Training Document Meshing -25
go below minimum
Min and Max
- Try to maintain current triangle size
- If triangle size is larger than max, surface is refined
- If triangle size is smaller than min, surface is coarsened
Lecture - STAR-CCM+ - Meshing Reference valuespecification
Min only- Models will try and maintain current local triangle size
- When local triangle size is below minimum, it will becoarsened
7/23/2019 Lec STARCCM FoundationTrainingV2.0
218/342
CD-adapco, Americas Agency Training Document Meshing -26
7/23/2019 Lec STARCCM FoundationTrainingV2.0
219/342
Lecture - STAR-CCM+ - Meshing Surface Wrapper -Example
7/23/2019 Lec STARCCM FoundationTrainingV2.0
220/342
CD-adapco, Americas Agency Training Document Meshing -28
Lecture - STAR-CCM+ - Meshing Surface Wrapper -Example
7/23/2019 Lec STARCCM FoundationTrainingV2.0
221/342
CD-adapco, Americas Agency Training Document Meshing -29
Lecture - STAR-CCM+ - Meshing - Remesher
What does the Remesher do?The remesher re-triangulates and improves the overallquality of the surface and optimizes it for generation of avolume mesh.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
222/342
CD-adapco, Americas Agency Training Document Meshing -30
Lecture - STAR-CCM+ - Meshing - Remesher
The remesher improves triangulation quality as shown below.
7/23/2019 Lec STARCCM FoundationTrainingV2.0
223/342
CD-adapco, Americas Agency Training Document Meshing -31
Lecture - STAR-CCM+ - Meshing VolumeMeshing
What are the types of volume meshes that can begenerated by STAR-CCM+?
TetrahedralMesh
PolyhedralMesh
Trimmed Mesh(Advanced Hexahedral)
7/23/2019 Lec STARCCM FoundationTrainingV2.0
224/342
CD-adapco, Americas Agency Training Document Meshing -32
Lecture - STAR-CCM+ - Meshing VolumeMeshing
TetrahedralMeshTetrahedralMeshTetrahedralMeshTetrahedralMesh
7/23/2019 Lec STARCCM FoundationTrainingV2.0
225/342
CD-adapco, Americas Agency Training Document Meshing -33
Lecture - STAR-CCM+ - Meshing VolumeMeshing
PolyhedralMeshPolyhedralMeshPolyhedralMeshPolyhedralMesh
7/23/2019 Lec STARCCM FoundationTrainingV2.0
226/342
CD-adapco, Americas Agency Training Document Meshing -34
Lecture - STAR-CCM+ Meshing VolumeMeshing
7/23/2019 Lec STARCCM FoundationTrainingV2.0
227/342
CD-adapco, Americas Agency Training Document Meshing -35
Le
Top Related