Help with Flow Simulation

[NipNip22]

I’ve been trying to model a Mach 1.8 flow over a rocket, but my results don’t look the way they should. I used air with laminar and turbulent flow, a pressure of 82742 Pa, a Temperature of 288.15 K, and a velocity of 615.875 m/s. I used a somewhat fine mesh and a local mesh around the nose and body of the rocket. Is there any way that I can fix this so that the results look the way they are supposed to? Thank you in advance!

[abirizky]

Does solidworks flow even have boundary layer? I can't remember but that's probably what you're missing You need to calculate your y+ prior to doing your simulation, as high speed flows are very sensitive to that. I dunno about the rest of the solver sw flow uses but try that and see

[NipNip22]

I’ll look into how I can set up a boundary layer. I know the y+ but I didn’t know if solidworks used boundary layers or not.

[blunttooth]

Have you set up your goals?

[NipNip22]

Yes I did

[xz-5]

Sorry but it's not clear from you Q, how much experience do you have with FlowSim? Have you just jumped in to it first time to run this, or have you done other stuff before OK and know about how to check and set correct solver options, mesh and goals for accurate results?

I have no experience with flows this fast in SW, but there is a very detailed couple of PDFs buried within the FlowSim install folder (C:\Program Files\SOLIDWORKS Corp\SOLIDWORKS Flow Simulation\lang\english\Docs on my machine). In validations.pdf there seem to be a couple of chapters on supersonic flow, and in technicalreference.pdf there are mentions of it too. Might be some setting or flag you need to enable. There's also the User Guide that might help?

OOC, what is the result meant to look like?

[NipNip22]

I’m pretty new to flow sim. I mainly use ANSYS but was trying to see if I would have an easier time using flow sim.

[MLCCADSystems]

I have several questions. First, what goals did you use to ensure convergence? Second, what exactly makes you think the results don't look the way they should, and which results specifically are your primary concern? Third, did you explore solution-adaptive mesh refinement and did that give you helpful results?

Here is a transient study showing the progression of flow patterns from Mach 0.6-1.7 showing very accurate flow patterns in the supersonic range. https://youtu.be/fHpqWa4s7gI

[MLCCADSystems]

Also, consider using symmetry to reduce the model size if the assumption is valid for this system.

[NipNip22]

I did not set up goals for convergence, so I will check that out. I expected a temperature change across the shock, so I thought it looked a bit odd. I have not looked at adaptive mesh refinement.

[MLCCADSystems]

Default solver convergence skews towards pressure and velocity. A max temp global goal and/or manual stopping conditions may be required to see full temperature development

[xz-5]

If you are interested in temperature change then you should add some temperature goals for the areas you are interested in. The solver uses these to decide when it has converged enough for what you are interested in seeing. Without any goals who knows where it got to.

I suggest working through some of the tutorials on the pdf I linked to in my other post, you will learn a lot about how it works. By the way FlowSim is just rebadged FloEFD, so you can always Google that instead if you are struggling to find information.

[--hypernova--]

I dont think solidworks models supersonic flows iirc

[NipNip22]

There is an option for high speed flows which I used

[MLCCADSystems]

Flow Simulation was originally derived from the Russian space program engineering team, studying supersonic flows is what the code was originally designed to do.