Supersonic Inflow

Project Support
1

I have 2 related questions:

  • Is the “Compressible Flow” solver density-based, or pressure-based? This post from 2018, Compressible Flow Simulation - Retro Propulsion - #9 by dylan, suggests at the time the user could choose. Since there is currently (2025) no choice, how does the solver work? Is there documentation?
  • Ultimately, I am trying to simulate a supersonic jet. (Imagine a rocket engine with a converging-diverging nozzle, blasting into the environment.) I’m only interested in the jet, not the internal nozzle flow. I tried specifying the velocity at the boundary of my ambient environment. When that value is subsonic (10 m/s, 100 m/s, etc), no problem. But as soon as I get to sonic (~ 340 m/s), the solution cannot converge. So, do I need to “create” my own supersonic by modeling the CD nozzle (which is also providing unstable), or am I missing the correct boundary condition that would enable a supersonic inlet to be specified? Ultimately, I want to apply 650 m/s (incoming) at the boundary of my domain (roughly M ~ 2).

Thank you

2

Hey @lelandswimsz ,

The compressible solver is pressure-based and is therefore only suitable for Mach < 1. Feel free to take a look at this post that was trying to do something similar.

For supersonic flows, the multi-purpose solver would be the solution. However, this is a paid solver and is not accessible with a community account.

Best,
Satvik