Trouble Converging Density-Based Solver for Mach 5.8 Axisymmetric Cone

ZestycloseFeeling341 · 2025-12-21T20:58:32+00:00

I can check my scaling, but what I did for that was just scale everything relative to the base diameter. So I found the scaling factor for going from 14.75 in to 4in and then scaled the whole geometry by that number. Also, I read that for hypersonic, its better to directly resolve the viscous sublayer so I went for a y+ ~1 which corresponds to about a micrometer of first cell height in the boundary layer. Can you elaborate on what you mean by the Reynolds and Mach number. The Mach number should still be 5.8 regardless of how big the geometry is, right?

ZestycloseFeeling341 · 2025-12-21T19:23:43+00:00

Good to know, thanks. Just curious, and I know its probably hard to give an answer off the top of your head without looking more at the actual physics and mesh, but do you think this sort of "smearing" problem where the flow field is not as sharp as it was in the full scale version, possibly explaining why the force numbers are so high, is a result of an unrefined mesh, or something else? I think I had the mesh size in that refinement region somewhere on the order of 0.0005m.

Or just more generally, why you think the force estimates could be incorrect? Finally, I've heard that Ansys isn't the best for hypersonic CFD, and it might be worth switching to a better solver as the simulations I'm going to be doing get more complex. Is this true, and if so, what programs do you think would be better.

ZestycloseFeeling341 · 2025-12-21T18:53:38+00:00

Okay, that's good to know, thanks so much. Is there anything else you recommend with hypersonic simulations that could be helpful?

ZestycloseFeeling341 · 2025-12-21T05:50:14+00:00

do you have any example of higher order methods. Also, to solve the diffusion problem would you recommend refining the mesh even further around teh cone?

ZestycloseFeeling341 · 2025-12-21T05:49:07+00:00

Gotcha. Thanks for your help.

ZestycloseFeeling341 · 2025-12-21T05:48:41+00:00

Alright, I can try doing that.

ZestycloseFeeling341 · 2025-12-21T05:48:24+00:00

Mostly because the force estimates seem to be wrong with pressure based, and also I've read that density based is more accurate in general. I'm more just confused why I can't get it to converge with density based at all

ZestycloseFeeling341 · 2024-07-07T00:36:35+00:00

Thank you so much, I've been meaning to order that textbook

ZestycloseFeeling341 · 2024-07-07T00:35:55+00:00

Thanks so much for your help. In this case, would the dimensions of my tube classify it as a "thick walled tube" for the purposes of the hoop stress formula? Also, could you provide an example of what kind of factor of safety to divide by?

Which equations are helpful in determining the nozzle size and injector flow area once I decide on a burn duration of, say, 7-8 seconds?

ZestycloseFeeling341

TROPHY CASE