In this session we solve an unsteady water flow around a two-dimensional cylinder using FIDAP.
 

Step-by-Step FIDAP Instructions for Setting up the model

1. Starting the FID AP GUI:

cd /tmp

mkdir mydir (make a new directory)

cd mydir (Always start in a new, empty directory)

fidap -id 2Dcyld -gui (start a FIDAP session named 2Dcyld)

click the "FIDAP version window" to remove it

• Click FI-GEN
• Click Accept (after a few seconds a graphical window appears)

• select Point
• click Add under COMMAND OPTION
• Enter the coordinates of the following 7 points: (0,0), (10,0), (10,5), (0,5), (2.0,2.5), (2.5,2.0), (3.0,2.5) (will be referred to as points 1, 2, 3, 4, 5, 6, 7 in this order)
• Move the cursor into the graphical window and type the letter "F" to bring all the 7 points into the window (you should see all the 7 points, each marked by a plus sign)
• Click Curve (1)
• Select ADD Line under COMMAND OPTION
• Left click the points 1-2-3-4-1 in order in the graphical window, and then right click
• Select Curve(2)
• click ADD circle
• Left click points 5, 6, and 7, then right click (a circle is drawn)
• Select Surface
• Click ADD by W/F
• Left click the 4 lines connecting the points 1-2, 2-3, 3-4, 4-1 in order, then right click

1. Click Mesh Edge , Select ADD
2. Input 25 in the "Interval" box field
3. Left click the two vertical lines connecting the points 4-1,2-3;
4. Right click (you should see 26 nodes on each of the vertical line)
5. Input 40 in the "Interval" box field
6. Left click the two horizontal lines connecting the points 1-2,3-4; then right-click
7. Input 20 in the "Interval" box field
8. Left click the circle, Right click
9. Select Mesh Loop , click Add Pave
10. Left click the 4 lines connecting the points 1-2, 2-3, 3-4, 4-1 in order, then right click
11. Left click the circle, then right click
12. Select Mesh Face, click ADD
13. left-click on the dark blue surface cross bar, right-click
14. left-click on the outside square, then left-click on the inner circle, right-click
15. Select Bndry Edge , click Add
16. Select Layers under BOUNDARY EDGE DEFAULTS
17. Input 0.2 in the Height 1 field, 1.1 in the Growth factor field, and 3 in the No. Layer field
18. left-click on the mesh face boundary, right click
19. left-click on the circle, right click (You should see Be mark near the circle)
20. Select Mesh Face, click Mesh
21. Click "All" under SELECT OPTION
22. Click "Pave" under MESH FACE DEFAULTS
23. Input "fluid" in the "Entity" box
24. Right click in the graphical window (Now mesh is being generated, this may take a few minutes)

1. Click Mesh Edge
2. Select MESH MAP
3. Left click the line connecting points 1 and 2
4. Input "bottom" in the "Entity" field
5. Right click in the graphical window
6. Left click the line connecting points 3 and 4
7. Input "top" in the "Entity" field
8. Right click in the graphical window
9. Left click the lines connecting points 4-1
10. Input "inlet" in the "Entity" field
11. Right click in the graphical window
12. Left click the lines connecting points 2-3
13. Input "outlet" in the "Entity" field
14. Right click in the graphical window
15. Left click the cylinder
16. Input "cylinder" in the "Entity" field
17. Right click in the graphical window
18. Click END once to exit FIGEN

1. Click FIPREP, Select "Entity"
2. Left click the question mark to select "fluid" entity
3. Input "Fluid" in the ENTITY TYPE field, Right click ADD-ADD (REPEAT)
4. Left click the question mark to select "bottom" entity
5. Input "plot" in the ENTITY TYPE field, Right click ADD-ADD (REPEAT)
6. Repeat this for the other boundary entities: "top", "inlet", "outlet", "cylinder".

1. Click Properties
2. Click "DENSITY"
3. Input 0.998 in the MODEL TYPE-CONSTANT field
4. Click ADD
5. Click "VISCOSITY"
6. Input 0.01003 in the MODEL TYPE-CONSTANT field
7. Click ADD

1. Click Boundary C., Click BCNODE
2. Right-click exclamation point next to DEGREE of FREEDON, Pick VELOCITY
3. Right-click exclamation point next to REGION SELECTION, Pick ENTITY
4. Left-click question mark beside REGION SELECTION field, Pick "cylinder"
5. Right-click exclamation point next to VALUE GENERATION field, Pick Zero
6. Right-select ADD(REPEAT)
7. Right-click exclamation point next to DEGREE of FREEDON
8. Pick UX
9. Left-click question mark beside REGION SELECTION field, Pick "inlet"
10. Right-click exclamation point next to VALUE GENERATION field
11. Set CONST ANT to 1.0
12. Right-select ADD(REPEAT)
13. Right-click exclamation point next to DEGREE of FREEDON
14. Pick UY
15. Left-click question mark beside REGION SELECTION field, Pick "inlet"
16. Right-click exclamation point next to VALUE GENERATION field
17. Pick Zero, Right-select ADD (REPEAT)
18. Left-click question mark beside REGION SELECTION field, Pick "top"
19. Right-click exclamation point next to VALUE GENERATION field
20. Pick Zero, Right-select ADD(REPEAT)
21. Left-click question mark beside REGION SELECTION field, Pick "bottom"
22. Right-click exclamation point next to VALUE GENERATION field
23. Pick Zero, Right-select ADD

1. Select Simulation
2. Click EXECUTION
3. Change EXECUTION MODE to NEWJOB
4. Click ADD
5. Click PROBLEM
6. Change SIMULATION TYPE to TRANSIENT
7. Change CONVECTIVE TERM to NONLINEAR
8. Click ADD
9. Click TIMEINTEGRATION
10. Set NSTEPS=60
11. Set TSTART=0.0
12. Set DT=0.05
13. Click ADD
14. Click END to exit FIPREP

1. Click CREATE
2. Select Create
3. Click ACCEPT

1. Click RUN
2. Pick FISOLV
3. Pick FOREGROUND
4. Click ACCEPT (Now relax and wait for the simulation to finish, this may take a minute or two)

1. Click IDENT
2. Click ACCEPT
3. Click FIPOST
4. Click ACCEPT

1. Click Vector
2. Click Accept

1. Click Utility
2. Select TIMESTEP
3. Set to desired time step, click ADD
4. Click Contour
5. Right-click exclamation point next to DEGREE of FREEDON
6. Pick STREAMLINE
7. Input 60 in the CONTOUR LEVELS-AUTOMATIC field (this will draw 60 contour levels in stead of 10 by default).
8. Click ACCEPT (You can clearly see the re-circulation region)

15. Plot and read results on a line

1. PLOT-LINE: Degree of freedom = UX, LINE DEFINITION=PVECTOR, ACCEPT
2. INPUT: 0.,2.5,0.0,1.,0.0,0.0
3. Also check the results in the *.FIOUT file

/ Journal File for GAMBIT 1.3.0
/ File opened for write Wed Apr  4 11:19:03 2001.
identifier name "cylind" new saveprevious
undo begingroup
vertex create coordinates 0 0 0
undo endgroup
undo begingroup
vertex create coordinates 5 0 0
undo endgroup
undo begingroup
vertex create coordinates 10 0 0
undo endgroup
undo begingroup
vertex create coordinates 10 5 0
undo endgroup
undo begingroup
vertex create coordinates 5 5 0
undo endgroup
undo begingroup
vertex create coordinates 0 5 0
undo endgroup
undo begingroup
/
vertex create coordinates 2.5 2.510 0
/ This introduce a little bit of asymmetry to the domain to help generate
/ vortex shedding
/
undo endgroup
edge create radius 0.5 startangle 45 endangle 135 center "vertex.7" xyplane arc
edge create radius 0.5 startangle 135 endangle 225 center "vertex.7" xyplane arc
edge create radius 0.5 startangle 225 endangle 315 center "vertex.7" xyplane arc
edge create radius 0.5 startangle 315 endangle 45 center "vertex.7" xyplane arc
vertex connect "vertex.1" "vertex.2" "vertex.3" "vertex.4" "vertex.5" \
  "vertex.6" "vertex.7" "vertex.8" "vertex.9" "vertex.10" "vertex.11" \
  "vertex.12" "vertex.13" "vertex.14" "vertex.15" real
edge create straight "vertex.1" "vertex.2" "vertex.3" "vertex.4" "vertex.5" \
  "vertex.6"
edge create straight "vertex.6" "vertex.1"
edge create straight "vertex.5" "vertex.2"
edge create straight "vertex.6" "vertex.9"
edge create straight "vertex.5" "vertex.8"
edge create straight "vertex.2" "vertex.13"
edge create straight "vertex.11" "vertex.1"
face create wireframe "edge.10" "edge.15" "edge.2" "edge.12" real
face create wireframe "edge.12" "edge.1" "edge.13" "edge.9" real
face create wireframe "edge.4" "edge.14" "edge.11" "edge.13" real
face create wireframe "edge.14" "edge.3" "edge.15" "edge.5" real
face create wireframe "edge.6" "edge.7" "edge.8" "edge.11" real
undo begingroup
edge picklink "edge.10"
edge mesh "edge.10" successive ratio1 0.97 ratio2 0.97 intervals 40
undo endgroup
undo begingroup
edge picklink "edge.11" "edge.7"
edge mesh "edge.7" "edge.11" successive ratio1 0.98 ratio2 0.98 intervals 60
undo endgroup
undo begingroup
edge picklink "edge.4"
edge mesh "edge.4" successive ratio1 0.99 ratio2 0.99 intervals 60
undo endgroup
undo begingroup
edge picklink "edge.3" "edge.2" "edge.1"
edge mesh "edge.1" "edge.2" "edge.3" successive ratio1 1 intervals 40
undo endgroup
undo begingroup
edge picklink "edge.12"
edge mesh "edge.12" successive ratio1 0.97 intervals 40
undo endgroup
undo begingroup
edge picklink "edge.13"
edge mesh "edge.13" successive ratio1 0.97 intervals 40
undo endgroup
undo begingroup
edge picklink "edge.15"
edge mesh "edge.15" successive ratio1 1.03093 intervals 40
undo endgroup
undo begingroup
edge picklink "edge.14"
edge mesh "edge.14" successive ratio1 0.97 intervals 40
undo endgroup
undo begingroup
edge picklink "edge.5" "edge.9"
edge mesh "edge.9" "edge.5" successive ratio1 1 intervals 40
undo endgroup
undo begingroup
edge picklink "edge.6" "edge.8"
edge mesh "edge.8" "edge.6" successive ratio1 1 intervals 40
undo endgroup
face mesh "face.1" "face.2" "face.3" "face.4" "face.5" map size 1
face delete "face.5" onlymesh
undo begingroup
edge delete "edge.8" keepsettings onlymesh
edge mesh "edge.8" successive ratio1 0.99 intervals 50
undo endgroup
undo begingroup
edge delete "edge.6" keepsettings onlymesh
edge mesh "edge.6" successive ratio1 1.0101 intervals 50
undo endgroup
face mesh "face.5" map size 1
solver select "FIDAP"
physics create "fluid" ctype "FLUID" face "face.1" "face.2" "face.3" "face.4" \
  "face.5"
physics create "inlet" btype "PLOT" edge "edge.10"
physics create "top" btype "PLOT" edge "edge.9" "edge.8"
physics create "bottom" btype "PLOT" edge "edge.5" "edge.6"
physics create "outlet" btype "PLOT" edge "edge.7"
physics create "cylinder" btype "PLOT" edge "edge.4" "edge.1" "edge.2" \
  "edge.3"
export fidap "cylind.FDNEUT"
/ File closed at Wed Apr  4 11:53:02 2001, 15.56 cpu second(s), 4840040 maximum memory.

/
/          CONVERSION OF NEUTRAL FILE TO FIDAP Database
/
FICONV( NEUTRAL )
INPUT( FILE="cylind.FDNEUT" )
OUTPUT( DELETE )
END
/
/
TITLE
cylind
/
FIPREP(  )
/
EXECUTION( ADD, NEWJ )
/
PROBLEM( ADD, 2-D, INCO, TRAN, LAMI, NONL, NEWT, MOME, ISOT, FIXE, SING )
/
/ TIMEINTEGRATION( ADD, BACK, NSTE = 201, TSTA = 0, DT = 0.25, FIXE )
/ TIMEINTEGRATION( ADD, BACK, NSTE = 201, TSTA = 50.25, DT = 0.25, FIXE )
TIMEINTEGRATION( ADD, BACK, NSTE = 401, TSTA = 100.50, DT = 0.25, FIXE )
SOLUTION( S.S. = 50, VELCONV = .001, RESCONV = .001)
/
POSTPROCESS(NBLOCKS=1)
1 401 4
/
DATAPRINT( ADD, CONT )
PRINTOUT( ADD, NONE, BOUN )
/
ENTITY( ADD, NAME = "fluid", FLUI )
ENTITY( ADD, NAME = "bottom", PLOT )
ENTITY( ADD, NAME = "top", PLOT )
ENTITY( ADD, NAME = "inlet", PLOT )
ENTITY( ADD, NAME = "outlet", PLOT )
ENTITY( ADD, NAME = "cylinder", PLOT )
/
DENSITY( ADD, SET = 1, CONS = 0.998 )
VISCOSITY( ADD, SET = 1, CONS = 0.01003 )
/
/ ICNODE( ADD, VELO, ZERO, ENTI = "fluid", X, Y, Z )
/ To read steady-state flow field as the initial condition:
/ change *.FDPOST to *.FDREST
/ and then
ICNO (VELO, READ)
/
BCNODE( ADD, VELO, ENTI = "cylinder", ZERO, X, Y, Z )
BCNODE( ADD, UY, ENTI = "inlet", ZERO )
BCNODE( ADD, UX, ENTI = "inlet", CONS = 1.00 )
BCNODE( ADD, UY, ENTI = "bottom", ZERO )
BCNODE( ADD, UY, ENTI = "top", ZERO )
/
END(  )

/ change *.FDPOST to *.FDREST
/ and then
ICNO (VELO, READ)
/