Velocity profile for flow in a cylinder

[Saeed]

Hello,

I hope you are doing well. I am trying to simulate the flow in a cylinder that has solid geometry in the center and look at velocity profile around that solid geometry. the flow is coming in from the bottom and goes up, there is a small space around the solid geometry that allows the flow to pass. I am looking at the flow from the front and top (exactly above the solid geometry) and I am noticing the velocity profilce is not symmetri any more in higher velocity. The mesh in both is the same and the geometry itself is symmetry. they are both 3D, laminar and with steady state condition. in both the residuals are set at 1e-9. I was wondering if this is normal or there is some issue with it ?

Thanks

 

[Rob]

Assuming the mesh is well resolved, run another 50-100 iterations and have a look at the results again. I suspect you're seeing a real effect, and the dip in the end of the cut out may enhance that effect. Have a look at "eddy shedding", "coanda effect" and "power fluidics" for some background reading. 

[Saeed]

Thank you Rob for your help.

I have a very fine mesh. I also tried 16 ml/min and got the following results. can you please let me know if you still think thay the results are real effect?

Best,

[Rob]

They're possible but I can't say without a lot more images. What does the rest of the domain look like? 

[Saeed]

Hi Rob,

 

Thank yout reply. I have also another design which has a cone shape cavity. this one also does not show symmetry even at 8 ml/min. can you please let me know if this one also looks realistic?

d

[Rob]

I can't tell you without doing a detailed study which I'm not permitted to do. However the contour is showing asymmetry. Replot with node values off to see if the mesh resolution is suitable.