[efirvida]

Hi, in the follow image I show my case setup, the main idea is to get the Cd of well documented shapes, starting by the thin plate.



To do this i´m using simpleFoam, I upload my case setup too. The simulation runs without problem but I can´t never reach the Cd=1.9 for Re > 10e4 as the reference value. it always give me Cd > 3. So i´m not sure about what i´m doing wrong.

[piu58]

You cannot expect a correct result if you run this high Re numbers with a laminar solver. Even with advanced turbulence modesl it is hard to get an deviation as low as 20%. It is nearly impossible to confirm the drag crisis at even higer Re numbers.

[efirvida]

Originally Posted by piu58

You cannot expect a correct result if you run this high Re numbers with a laminar solver. Even with advanced turbulence modesl it is hard to get an deviation as low as 20%. It is nearly impossible to confirm the drag crisis at even higher Re numbers.

Hi. thanks for your reply and, sorry about my late response. I update my case using different turbulence models (k-e,k-w,k-w-sst) and getting good results with that.

Now I have a problem, I have same case, but I change the plate, with a square cylinder, of 1m*1m of size. When I use the case configuration, I get Cd from 1.6 to 1.8 and the reference value must be from 2.1 to 2.3 so the prediction its not good. And I dont understand why, If my case was correct for the previous geometry, rigth now I only change the width of the plate to be equal to the heigth.
But now think as i know if the relation of heigth/width increase the Cd have to decrees, its not a rule but that what I know and what my simulation say. but the books says other thing.

Well... I made another test changing the solver to pimpleFoam to made the case transient, and with this I get the 2.2 average value of the Cd. But if I use pimpleFoam in the thin plate, I get a Cd, over 4. So I dont have a clue of how to set a basic case to this kind of geometries to get the referenced values of the Cd.

[avc18]

Hi,



I saw your post and I was wondering if you still have the files and you can upload them here. I am trying to solve a 2D incompressible flow past a square cylinder and I cannot get the right solution, after the vorteces start shedding. Maybe I can get some insight with the problem.