Coupling incompressible and compressible two-phase flow...
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Introduction Details of the implementation Validation cases Future work Coupling incompressible and compressible two-phase flow solvers in a numerical wave tank Based on OpenFOAM & FOAM-Extend projects Pedro Martínez Ferrer, Ling Qian, Derek Causon, Clive Mingham and Zhihua Ma CMMFA Research Group, Manchester Metropolitan University Streatham Court Theatre, Exeter, 2016/04/19 1 / 17
Transcript of Coupling incompressible and compressible two-phase flow...
Introduction Details of the implementation Validation cases Future work
Coupling incompressible and compressibletwo-phase flow solvers in a
numerical wave tankBased on OpenFOAM & FOAM-Extend projects
Pedro Martínez Ferrer, Ling Qian, Derek Causon, CliveMingham and Zhihua Ma
CMMFA Research Group,Manchester Metropolitan University
Streatham Court Theatre,Exeter,
2016/04/191 / 17
Introduction Details of the implementation Validation cases Future work
Introduction
The construction of a numerical wave tank
Virtual Wave Structure Interaction (WSI) SimulationEnvironment.
Involves:Coupling of different specialized solvers: potential,incompressible, compressible. . .Dynamic and overset meshes to accommodate 6DoFfloating body motions.FSI when the solid deforms.Collaborative environment with developers working indifferent aspects of the wave tank: SoFT project (EPSRC).
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Details of the implementation
wsiFoam code development
The OpenFOAM-based solver wsiFoam (Virtual WaveStructure Interaction) combines:
fnlpFoam (fully non-linear potential flow solver),*interFoam* (incompressible VOF solver),*compressibleInterFoam* (compressible VOF),a new set of interface boundary conditions,. . .
Uses a partitioned approach to solve different regions.Interface is implicitly treated as another face connectingtwo cells from different regions: two-way coupling!Couples regions associated to similar or different solvers.Performance is on a par with native solvers: ready to HPC!
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Details of the implementation
Solvers: system of equations
Incompressible and compressible formulations are displayed.Mass equations:
∂α
∂t+∇ · Uα+∇ · Ucα(1− α) = −
α
ρw
Dρw
Dt,
∂ρ
∂t+∇ · (ρU) = 0,
with ρw = ρw,0 + p/RwT , ρa = p/RaT (instead of ρa = ρa,0).Similar momentum equation for both solvers
∂ρU∂t
+∇ · (ρUU)−∇ · (µeff∇U) = σκ∇α− g · x∇ρ−∇pd.
An energy equation is used by the compressible solver:∂ρT∂t
+∇·(ρUT )−∆(µeffT ) = −(
α
cv,w+
1− αcv,a
)(∂ρk∂t
+∇ · (ρUk) +∇ · (Up)
).
A Poisson equation is derived from mass and momentumequations to solve for the pressure and update velocity.
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Details of the implementation
Coupling interface: boundary conditions
d
dP
dN
Specify the patch value:
φf =1
|dP − dN |(φP |dN |+ φN |dP |)
and the normal gradient patch value:
Sf ·∇φf =
(|Sf|
φN − φP
|d|
)(Sf · d|Sf||d|
),
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wsiFoam iterative procedure
FOR EACH ITERATION IN THE MAIN LOOP, DO1 Calculate the time steps of the I regions2 Calculate the time steps of the C regions3 Find the global (minimum) time step
FOR EACH I REGION, DO
FOR EACH I TRANSPORT EQUATION, DO1 Linearize2 Apply boundary and interface conditions3 Solve
END I TRANSPORT EQUATIONEND I REGION
FOR EACH C REGION, DO
FOR EACH C TRANSPORT EQUATION, DO1 Linearize2 Apply boundary and interface conditions3 Solve
END C TRANSPORT EQUATIONEND C REGION
4 Update the simulation timeEND MAIN LOOP
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wsiFoam directory structure
Schematic view of the wsiFoam directory (1 of 2).
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Details of the implementation
wsiFoam directory structure
Schematic view of the wsiFoam directory (2 of 2).8 / 17
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Validation cases
Validation case: “dam break” (Martin & Moyce, 1952)
Dam break of water simulated with wsiFoam usinginterFoam (left) and compressibleInterFoam (right).
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Validation cases
Validation case: “dam break” (Martin & Moyce, 1952)x 1/a
(−)
0
1
2
3
4
5
6
7
8
9
0 0.5 1 1.5 2 2.5 3 3.5 4
II-I
I-CMartin & Moyce (1952)
Murrone & Guillard (2005)Ma et al. (2014)
t√
g/a (−)
x 2/a
(−)
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 0.5 1 1.5 2 2.5 3 3.5 4
II-I
I-CMartin & Moyce (1952)
Murrone & Guillard (2005)Ma et al. (2014)
t√
g/a (−)
Normalized water front position (left) and water column height(right) evolution.
*P. J. Martínez Ferrer, D. M. Causon, L. Qian, C. G. Mingham, Z. H. Ma. A multi-region coupling scheme for
compressible and incompressible flow solvers for two-phase flow in a numerical wave tank. Computers & Fluids
125, 116–129 (2016).
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Validation cases
Validation case: “dam break”
Table: Water dam break benchmark: simulation speed up for a meshof 400× 120 cells; times are normalized by tref = 262.93 s.
Cores I C I-C
1 1.25 1.00 1.102 2.10 1.66 1.834 3.18 2.52 2.80
*P. J. Martínez Ferrer, D. M. Causon, L. Qian, C. G. Mingham, Z. H. Ma. A multi-region coupling scheme for
compressible and incompressible flow solvers for two-phase flow in a numerical wave tank. Computers & Fluids
125, 116–129 (2016).
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Validation cases
Validation case: “water column drop” (ISOPE, 2010)
Water column drop simulated with one region usinginterFoam (left) and with two regions using interFoam
and compressibleInterFoam (right).
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Validation cases
Validation case: “water column drop” (ISOPE, 2010)p
(bar
)
0
10
20
30
40
50
0.62 0.63 0.64 0.65 0.66 0.67
I (800 × 600)C (800 × 600)
I-C (800 × 600)2P (1600 × 1200)
t (s)
p(b
ar)
0
10
20
30
40
50
0.63 0.64 0.65 0.66 0.67 0.68 0.69
I-C (800 × 600)2P (1600 × 1200)
Braeunin et al. (2009)Guilcher et al. (2010)
Ma et al. (2014)
t (s)
Time history of the impact pressure at the centre of the tankfloor compared against published results and other OpenFOAM
reference solutions.*P. J. Martínez Ferrer, D. M. Causon, L. Qian, C. G. Mingham, Z. H. Ma. A multi-region coupling scheme for
compressible and incompressible flow solvers for two-phase flow in a numerical wave tank. Computers & Fluids
125, 116–129 (2016).
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Future work
Coupling FNLP solvers with NS solvers
Linear waves simulated with wsiFoam using fnlpFoam(left) and interFoam (right).
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Open-source overset strategy
Oscillating floating box simulated with dynamic mesh (left)and overset mesh (right).
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Conclusions
wsiFoam has been developed according to professionalsoftware standards under the SoFT (EPSRC) project: git,doxygen, wiki website, etc.Interface boundary conditions have been validated and theresults have been published: Martínez Ferrer et al. (2016).Coupling between FNLP & NS solvers is being currentlyinvestigated.Overset strategies are currently being developed.FSI to be integrated to account for hydroelasticity effects.We aim to keep our contributions open-source to enhancecollaboration with the scientific community under theCCP-WSI (EPSRC) project.
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Thank you
Thank you for your attention!
Find us on:1 Twitter: @CMMFA2 Facebook: CMMFA3 Web: http://www.scmdt.mmu.ac.uk/cmmfa/
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