MEEG 681 / MEEG481
Computer Solution of Engineering Problems
Computer Session 8b

Here we solve the same steady and unsteady water flow around a two-dimensional cylinder using FLUENT.
 
Results for steady-flow simulations at Re around 30 (u=0.3 cm/s, rho = 0.998 g/cm^3, nu = 0.01003 g/cm.s.)
The gambit files are: c16by8map.gambit-fidap , c16by8map.gambi t-fluent

Drag force comparison:

Total Drag, dyne/cm Drag Coefficient
FIDAP 0.09267 2.06
FLUENT 0.1006 2.24
Notes:
(1) In FIDAP, drag force is obtained by COMPUTATION / STRSPRINT, entity = cylinder, the total force in x dirextion is the drag.
(2) In FLUENT, the drag force can be computed by Report/Forces. You can also obtain the drag coefficient directly if you set the reference table correctly by Report/Reference Values.
(3) I also noted that I needed to set the solver to "coupled" in FLUENT to obtain the flow correctly.


Results for unsteady flow at Re=100

Play an animation movie based on a FLUENT simulation: Movie
 
The mesh was the same as the above.
The setup for unsteady flow in Fluent is described well in http://bubble.me.udel.edu/wang/teaching/MEx81/fluent-help/html/tg/node48.htm

See, in particular, Steps 8, 9, and 10.

When I solved the problem, I ran for about 200 time steps with a fixed time step size of 0.25.

Then I made movies after that.