CFD multi region mesh error

I am using CFD to study pressure variation on a moving body.When I run the simulation i shows the following error

“A multi-region mesh was assigned - this analysis-type requires a single-region mesh.”
Link to the project: https://www.simscale.com/projects/jprasath/pressure_analysis_4/

Hey, @jprasath !

For incompressible simulations, you only need the flow domain. To fix the issue that you’re having right now, you need to re-run the enclosure operation with “Keep existing parts” turned off:

You’ll also have to make another mesh, as the one you’re using right now contains the solid volume.

Furthermore, your boundary conditions are a little weird. Try using a wall (slip) condition for the 4 faces around the torpedo and pressure outlet for the face downstream.

Let us know if you run into more issues!

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Okay i will run the simulation with ‘existing part off’.And for the boundary conditions, i wanted to simulate torpedo moving in the ocean at a particular depth.And after some distance the effect on ocean due to motion of torpedo is negligible that is why i kept all the faces at same pressure.Also is there a way in which i can specify both inlet velocity and pressure,as when i specify both the simulation wont run saying that there is multiple boundary conditions specified for the same face.
And thank you for helping me out

For incompressible simulations, what really matters is the pressure gradient. It won’t make a difference if your system is at 1 atm or 2.

You can even make the following test: set pressure outlet to 0. Let’s say this way you get 100 Pa at the inlet. If you run the same simulation setting pressure outlet to 10000 Pa, the pressure at the inlet will be 10100 Pa.

If you specify velocity and pressure at the inlet + pressure at the outlet, you’ll probably end up overspecifying the boundary conditions. As a result, issues with continuity can arise.