Fluent12 Lecture03 Solver Basics
-
Upload
ijaz-fazil -
Category
Documents
-
view
235 -
download
2
Transcript of Fluent12 Lecture03 Solver Basics
-
7/25/2019 Fluent12 Lecture03 Solver Basics
1/20
3-1ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Chapter 3
Solver Basics
Introductory FLUENTTrainingSharif University of Technology
Lecturer: Ehsan Saadati
ehsansaadati!g"ailco"
-
7/25/2019 Fluent12 Lecture03 Solver Basics
2/20
Solver Basics
3-2ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training ManualFLUENT #$ %UI Navigation
The FLUENT %UI is arranged such that the tas&s are generally
arranged fro" top to 'otto" in the pro(ect setup tree
Selecting an ite" in the tree opens the relevant input ite"s in the
center pane
$ %eneral
$ )odels$ )aterials
$ Boundary
Conditions
$ Solver Settings
$ Initiali*ation and
Calculation
$ +ostprocessing
-
7/25/2019 Fluent12 Lecture03 Solver Basics
3/20
Solver Basics
3-3ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training ManualScaling the )esh and Selecting Units
,hen FLUENT reads a "eshfile -"sh./ all physical
di"ensions are assu"ed to 'ein units of "eters$ If your "odel 0as not 'uilt in
"eters/ then it "ust 'e scaled$ 1erify that the 2o"ain Etents
are correct after scaling the"esh
,hen i"porting a "esh under,or&'ench/ the "esh does notneed to 'e scaled4 ho0ever/ theunits are set to the default )5Ssyste"
6ny 7"ied8 units syste" can'e used if desired$ By default/ FLUENT uses the SI
syste" of units -specifically/)5S syste".
$ 6ny units can 'e specified inthe Set Units panel/ accessedfro" the top "enu
%e&ine 'nits(
-
7/25/2019 Fluent12 Lecture03 Solver Basics
4/20
Solver Basics
3-)ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training ManualTet User Interface
)ost %UI co""andshave a corresponding
TUI co""and$ )any advanced
co""ands are onlyavaila'le throughthe TUI
$ +ress the Enter &eyto display the
co""and set at thecurrent level
$ q"oves up one level
FLUENT can 'e runin 'atch "ode or
scripted using a(ournal file -see6ppendi.
6 TUI user guide is availa'le on the FLUENT User Services Centerwww.fluentusers.com
-
7/25/2019 Fluent12 Lecture03 Solver Basics
5/20
Solver Basics
3-*ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training Manual)ouse Functionality
)ouse 'utton functionality depends on the chosen solver -$2 9 32.and can 'e configured in the solver
2efault settings$ $2 Solver
Left 'utton translates9pans -dolly.
)iddle 'utton *oo"s
ight 'utton selects9pro'es
$ 32 Solver Left 'utton rotates a'out $ aes
)iddle 'utton *oo"s$ )iddle clic& on point in screen centers point
in 0indo0
ight 'utton selects9pro'es
etrieve detailed flo0 field infor"ation at point 0ith +ro'e ena'led$ ight;clic& on the graphics display
)ouse controls can 'e set to e"ulate those in ,or&'enchuire "ultiple "aterialsand dictate 0hich "aterialproperties "ust 'e defined
$ )ultiphase -"ultiple "aterials.$ Co"'ustion -"ultiple species.$ ?eat transfer -ther"al
conductivity.$ adiation -e"issivity and
a'sorptivity.
)aterial properties can 'e directly custo"i*ed as function ofte"perature9pressure$ Use of other solution varia'le-s. re>uires U2F
-
7/25/2019 Fluent12 Lecture03 Solver Basics
7/20
Solver Basics
3-ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training Manual)aterials 2ata'ases
FLUENT "aterials data'ase
$ +rovides access to a nu"'er
of pre;defined fluid/ solid and
"iture "aterials
$ )aterials can 'e copied to
the case file and edited if
re>uired
Custo" "aterial data'ase:
$ Create a ne0 custo" data'ase
of "aterial properties and
reaction "echanis"s fro"
"aterials in an eisting casefile for reuse in future cases
$ Custo" data'ases can 'e created/
accessed and "odified fro" the
standard "aterials panel in FLUENT
-
7/25/2019 Fluent12 Lecture03 Solver Basics
8/20
Solver Basics
3-!ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training Manual@perating Conditions
The @perating +ressure 0ith a eference
+ressure Location sets the reference
value that is used in co"puting gauge
pressures
The @perating Te"perature sets the
reference te"perature
-used 0hen co"puting
'uoyancy forces
Specified @perating
2ensity sets the referencevalue for flo0s 0ith 0idely
varying density
-
7/25/2019 Fluent12 Lecture03 Solver Basics
9/20
Solver Basics
3-9ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training Manual+arallel +rocessing
+arallel processing can 'e used to runFLUENT on "ultiple processors to
decrease turnaround ti"e and increasesi"ulation efficiency$ Critical for cases involving large "eshes
and9or co"ple physics$ FLUENT is fully paralleli*ed and capa'le of
running across "ost hard0are andsoft0are configurations/ such as co"puteclusters or "ulti;processor "achines
+arallel FLUENT can 'e launched eitherusing the syste" co""and pro"pt orusing the FLUENT Launcher panel$ For ea"ple/ to launch an n;C+U parallel
session/ use the co""andfluent 3d tn
The "esh can 'e partitioned either
"anually or auto"atically using a nu"'erof different "ethods$ Non;confor"al "eshes/ sliding "esh
interfaces and shell conduction *onesre>uire partitioning in serial
6 0e';'ased lecture is availa'le on theFLUENT User Services Center
-
7/25/2019 Fluent12 Lecture03 Solver Basics
10/20
Solver Basics
3-10ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training ManualSu""ary
This lecture has presented "any 'asic tas&s that are often perfor"ed
during a CF2 si"ulation setup
+arallel processing can 'e used to reduce calculation ti"e This is
advantageous only on large "eshes
6 later lecture contains "aterial related to the setup and solution ofti"e;dependent pro'le"s
@ther topics not discussed -see 6ppendi for infor"ation.
$ )esh heirarchy and relationships
$ eordering and "odifying the "esh in the solver
$ +olyhedral "esh conversion
$ Solution;'ased "esh adaption
-
7/25/2019 Fluent12 Lecture03 Solver Basics
11/203-11ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
6ppendi
-
7/25/2019 Fluent12 Lecture03 Solver Basics
12/20
Solver Basics
3-12ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training ManualFLUENT Aournals
FLUENT can 'e run in 'atch "ode using(ournal files
6 (ournal file is a tet file 0hich containsTUI co""ands 0hich FLUENT 0ill eecutese>uentially
The FLUENT TUI accepts a''reviations ofthe co""ands4 for ea"ple/$ ls Lists the files in the 0or&ing
folder
$ rcd eads case and data files$wcd ,rites case and data files$ rc/wc eads90rites case file$ rd/wd eads90rites data file$ it Iterate
TUI co""ands in a 'atch file can 'e usedto auto"ate operations in a non;interactive
"ode$ The TUI co""ands file/read-bcand
file/write-bccan 'e used for readingand 0riting the settings for a FLUENTsession to and fro" a file/ respectively
$ 6 0e';'ased training "odule is availa'le0hich eplains this process
; Read case file
rc example.cas.gz
; Initialize the solution
/sole/initialize/initialize-flow
; !alculate "# iterationsit "#
; $rite data file
wd example"#.dat.gz
; !alculate another "# iterations
it "#
; $rite another data file
wd example%##.dat.gz
; &xit '()&*+exit
,es
Sa"ple Aournal File
-
7/25/2019 Fluent12 Lecture03 Solver Basics
13/20
Solver Basics
3-13ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training Manualeading the )esh ones
In this ea"ple/ there are t0o cell *ones -fluid;upstrea" and fluid;
do0nstrea". Because of this/ FLUENT splits the eterior 0all *one into t0o *ones
-0all and 0all:DD#. This is 'ecause an eternal 'oundary cannotspan "ultiple cell *ones
FLUENT also splits the orifice plate into t0o 0alls also -plate andplate;shado0. since the plate *one is an internal 0all
inlet
otlet
/all
plate
plate-shao/
&li cell one
2efault;interior *one-s.can al0ays 'e ignored
-
7/25/2019 Fluent12 Lecture03 Solver Basics
14/20
Solver Basics
3-1)ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training Manual)esh Infor"ation and ?ierarchy
6ll "esh infor"ation is stored in the "esh file$ Node coordinates
$ Connectivity$ one definition
Si"ilar to the 0ay geo"etry is defined/ "eshentities o'ey a hierarchy:
$ Node Edge intersection 9 grid point$ Edge Boundary of a face -defined 'y
t0o nodes$ Face The 'oundaries of cells/ defined 'y
a collection of edges$ Cell The control volu"es into 0hich the
do"ain is discreti*ed$ one 6 collection of nodes/ edges/ faces
or cells
The co"putational do"ain is defined 'y all"e"'ers of the hierarchy
$ For fluid flo0 si"ulation only/ the do"ain consistsonly of the fluid region
$ For con(ugate heat transfer or fluid;structureinteraction pro'le"s/ the do"ain needs to includeany solid parts that are present
Boundary data is assigned to face *ones )aterial data and source ter"s are assigned to
cell *ones
Si"ple 32 "esh
Si"ple $2 )esh
Node
Boundary
Face
Cell
CellCenter
Cell Face
Node
BoundaryFace
Cell
Edge
-
7/25/2019 Fluent12 Lecture03 Solver Basics
15/20
Solver Basics
3-1*ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training Manualeordering and )odifying the %rid
The grid can 'e reordered so that neigh'oring cells are near eachother in the *ones and in "e"ory$ I"proves efficiency of "e"ory access and reduces the 'and0idth of the
co"putation
$ eordering can 'e perfor"ed for the entire do"ain or specific cell*ones
$ The 'and0idth of each partition in the grid can 'e printed for reference
The face9cell *ones can also 'e "odified 'y the follo0ing operationsin the %rid "enu:$ Separation and "erge of *ones
$ Fusing of cell *ones 0ith "erge of duplicate faces and nodes
$ Translate/ rotate/ reflect face or cell *ones
$ Etrusion of face *ones to etend the do"ain
$ eplace a cell *one 0ith another or delete it
ri 4eorer 5onesri 4eorer %o6ain
ri 4eorer Print an/ith
-
7/25/2019 Fluent12 Lecture03 Solver Basics
16/20
Solver Basics
3-1#ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training Manual+olyhedral )esh Conversion
6 tetrahedral or hy'rid grid can 'econverted to polyhedra in the FLUENT %UI
-not in the preprocessor.$ %enerate a tetrahedral "esh then convertinside FLUENT
$ 6dvantages I"proved "esh >uality Can reduce cell count significantly User has control of the conversion process
$ 2isadvantages: Cannot 'e adapted or converted again Cannot use tools such as s"ooth/ s0ap/ "erge
and etrude to "odify the "esh
T0o conversion options are availa'le in the%rid "enu:
$ Convert all cells in the do"ain -ecept hecells. to polyhedra
Cannot convert "eshes 0ith hanging nodes ?eCore "esh can 'e converted using the tpoly
standalone utility
$ Convert only highly s&e0ed cells to
polyhedra%rid +olyhedra Convert S&e0ed Cells
%rid +olyhedra Convert 2o"ain
Tet9?y'rid )esh
+olyhedral )esh
-
7/25/2019 Fluent12 Lecture03 Solver Basics
17/20
Solver Basics
3-1ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training Manual+rofile 2ata and Solution 2ata Interpolation
FLUENT allo0s interpolation of selectedvaria'le data on 'oth face *ones and cell
*ones 'y using profile files and datainterpolation files/ respectively$ For ea"ple/ a velocity profile fro"
eperi"ental data or previous FLUENT runat an inlet/ or a solution interpolated fro"a coarse "esh to fine "esh
+rofile files are data files 0hich containpoint data for selected varia'les onparticular face *ones/ and can 'e 'oth
0ritten and read in a FLUENT session
Si"ilarly/ Interpolation data files containdiscrete data for selected field varia'leson particular cell *ones to 'e 0ritten andread into FLUENT
7ile Pro&ile(8rite
7ile Pro&ile(4ea
7ile Interpolate(
-
7/25/2019 Fluent12 Lecture03 Solver Basics
18/20
Solver Basics
3-1!ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training Manual)esh 6daption
)esh adaption refers to refine"entand9or coarsening cells 0here neededto resolve the flo0 field 0ithoutreturning to the preprocessor
$ )ar& cells satisfying the adaptioncriteria and store the" in a 7register8
$ 2isplay and "odify the register ifdesired
$ Clic& 6dapt to adapt the cells listed intheregister
egisters can 'e defined 'ased on:$ %radients or isovalues of all varia'les$ 6ll cells on a 'oundary$ 6ll cells in a region 0ith a defined
shape$ Cell volu"es or volu"e changes$ y in cells ad(acent to 0alls
To assist adaption process/ you can:$ Co"'ine adaption registers$ 2ra0 contours of adaption function$ 2isplay cells "ar&ed for adaption$ Li"it adaption 'ased on cell si*e
and nu"'er of cells
efine Threshold should
'e set to #D of the valuereported in the )a field
-
7/25/2019 Fluent12 Lecture03 Solver Basics
19/20
Solver Basics
3-19ANSYS, Inc. Proprietary
2009 ANSYS, Inc. All rights reserve.April 2!, 2009
Inventory "002#00
Training Manual6daption Ea"ple Supersonic +ro(ectile
6dapt grid in regions of large pressure gradient to 'etter resolve the
sudden pressure rise across the shoc&
Initial )esh -%enerated 'y +reprocessor. +ressure Contours on Initial )esh
Large pressure gradient
indicating a shoc& -poor
resolution on coarse
"esh.
-
7/25/2019 Fluent12 Lecture03 Solver Basics
20/20
Solver Basics
3 20ANSYS, Inc. Proprietary April 2!, 2009
Training Manual6daption Ea"ple Supersonic +ro(ectile
Solution;'ased "esh adaption allo0s 'etter resolution of the 'o0
shoc& and epansion 0ave
)esh adaption yields
"uch 'etter resolution
of the 'o0 shoc&6dapted cells
in locations of
large pressure
gradients
6dapted )esh -)ultiple 6daptions
Based on %radients of +ressure.
+ressure Contours on 6dapted )esh