Bluff Body Simulation

Using SimScale Fluid Flow / CFD
1

Hi,
I have been trying to simulate a bluff body in SimScale, and I have consistently getting bad convergence. The residual - ‘p’ in particular is behaving weirdly.

I tried increasing the domain size, and it helped, but still I would like to understand the reason for this behavior.

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1 Like
2

Hi :grinning:

I would like to check the project if that’s alright, could you share a link, please?

Best regards,
Fillia

3

Hey!

The increased length of the enclosure is because I was getting weird results in smaller enclosures.

4

Hi @prateekjain0608,

  • Please set the “Potential flow initialization” to “yes” in Simulation control.
  • Your domain is too long and too coarse.
  • The mesh around the blunt body should be refined.
  • I suggest to mesh using TET mesh (not HEX), non physic, in order to avoid huge amount of cells at the domain edges.
  • Residuals fluctuation is due to vortex shedding: it is normal with blunt bodies.

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Take care,

Retsam

2 Likes
5

Hey, I used a longer domain because we were unsatisfactory results in smaller domain.

Here is the example, in this project: SimScale

You can compare: Fuselage 45m long enclosure simulation

  1. Pressure Force Z is oscillating. And also Pressure Force X is slightly oscillating.
  2. The residuals are also oscillating.

With: Fuselage 90m long enclosure → Hex Mod 0.06

  1. The residuals are drastically showing better convergence
  2. There is no oscillation in any of the forces.

Also, the option to select TET mesh is not available. Only three options are there - Standard, Hex, Hex Parametric.
I assumed you mean TET-dominant. If you mean Standard mesh, I can give it a try!

@Retsam, thanks for replying!

6

Hey, @1318980
Could you help on the above problem?