CFD Post Processing Error - The domain is blue everywhere

Using SimScale Fluid Flow / CFD
1

I am trying to do a CFD simulation of my UAV. the simulation is of incompressible flow with a flow velocity of 20m/s. Simulation completed successful there are no error.But, in postprocessing when i am trying to get pressure distribution on the surface of the UAV. Instead of get a colour gradient of pressure i am getting a solid colour. Is there some thing that i am doing wrong? if yes, please let me know

link to the model: https://www.simscale.com/workbench/?pid=7522918124449680190&mi=spec%3Af18dc664-84e4-4733-8ca2-5de22b669274%2Cservice%3ASIMULATION%2Cstrategy%3A19

2

Hi,

This happens because you don’t have a boundary condition on your UAV.

You should add a “no slip wall” boundary condition and select all faces of the UAV.

Regards

3

I think a slip-wall should still produce a pressure/force distribution over its surface. Still, you do need to follow @mgiannios fix and set walls to no-slip. I’m not sure if SimScale has already included the capability of integrating the pressure over a surface, but if not, check out this link and do it in Paraview

4

Thank you for your reply, I am gonna try that

5

I tried doing that and that didn’t work

6

Is my analysis correct? like the boundary conditions and setting

7

Hi there,

the issue with the post processing is that some “bad cells” with really high values exist, and they “drag” the full range of the scale. As a result, the normal values are all colored in blue.

full scale
full scale1628Ă—927 87.3 KB

Try setting the max number of the scale to 40. Then the different colors will appear:
40
401627Ă—939 92.5 KB

In order to locate the bad cells and refine the problematic areas, check the Isovolumes method here:

Best regards,
Fillia

8

This makes sense, but keep in mind that if a face doesn’t get assigned any boundary conditions, it will be automatically set to no-slip wall :slight_smile:

9

You can do this by setting a “Surface Data” set :smiley:

1 Like
10

Thank you for the reply.
I tried this for pressure contour but it didn’t work its still a solid colour when pressure is selected as the criteria

11

Your pressure has both really high and really low values, try to narrow the range like this:

pressure
pressure787Ă—824 36 KB

1 Like
12

Thank you, i was stuck here for days

1 Like
13

Thank you!

1 Like