Hi everyone,
Happy New Year!
I am carrying out a Simulation for Flow Past a Square Cylinder. I am using Ansys Fluent.
I get a very low value of Cd in the simulation. The solution converges but the value of Cd is pretty low. For a Re of 13000, the proper value is close to 2.1.
I will attach the results.
Simulation Details: Square cylinder with depth 0.1m, inside a circular domain of Dia 6 m
Inlet velocity 1 m/s,
Inlet BC:
k = (3/2)*(inlet velocity* Turbulence Intensity)^2
w = K^(1/2)/(0.09^(1/4)*Turbulence length scale)
Here I took Turbulence length scale = 0.07 x Domain Dia
Model: kw SST, Outlet (BC: Gauge Press = 0)
Earlier for a rectangular domain, I got a proper Cd value but with a Circular domain, I am unable to get a reasonable Cd value.
1) I want to know what possibly could result in this lower value of Cd and what I can do to solve it.
I was thinking of tweaking the Solutions Control (Non-iterative Time Advancement?) because the Residuals are diverging at the end and thought it would help.
2) Does Fluent require special considerations for the Circular domain?
Thank you for your time.
Have you used proper Reference values? if not then Cd won't be correct.
Mr. Mahabat Khan, thank you for your answer. I have checked the Reference values. I have updated the Area (in my 2D case the depth of the bluff body), the inlet velocity value, and the viscosity value as well. The turbulence parameter has also been initialized from the inlet boundary condition. I am not sure what else could go wrong.
Any insights are helpful.
Thanks.
Hi
1) When you use the KW SST model, it is better that keep the y+ near 1.
2) If the solution diverges, try to reduce the time step size.
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