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Flowsquare is an easy to use 2D CFD program that is free/cheap. It was developed by one guy (Yuki Minamoto) for educational purposes.
What makes it especially accessible is that the boundary layer conditions are just a bitmap. So you can set up your simulations in mspaint. Everything else is configured through a text document.
I figured with how much interest there is in miata aero, that some of you may get some use out of this. Its obviously nowhere near as capable as professional CFD software, but those packages are pretty challenging to use. This is a good way to make pretty pictures and maybe learn something along the way.
Almost forgot, heres the miata bmp and the config file (grid.txt). For some reason I cant upload a bmp, so its a png. Just open it in paint and save it as a bmp and it should work (it must be called bc.bmp)
I made .bmp files based on yours for hardtop and no hardtop, but when I try to use your grid file I get the attached error. Not sure what is going on there because there is nothing in the grid file called fname1 and there are no differences between your grid file and the default grid file aside from parameter values.
I am learning about the parameters in the grid file now. I did not pay enough attention to the aero work when I was on a formula SAE team, I am regretting that now!
Thats strange, are you creating a new simulation with a new name? It looks like its looking for a file in the dump folder, which is created in a simulation folder.
Can you screenshot (or cmd dir) the directory everything is in?
Thats strange, are you creating a new simulation with a new name? It looks like its looking for a file in the dump folder, which is created in a simulation folder.
Can you screenshot (or cmd dir) the directory everything is in?
Definitely strange, I had the same thought though. It's like the program is looking for an already existing project even though I am starting one from scratch. I run it, it fails with that error, then when I go back to the directory there is a folder with my project name. But nothing I found in that folder led me to getting it working. The strangest thing to me is that it works fine with the default grid.txt values.
Here is the directory before running the program...
EDIT...
So by process of elimination (changing params from defaults to your values until it broke) that the param causing the issue is the 06:sts (start time step). No clue why, because the error it gives doesn't really seem related to that, but that is the one that is breaking things.
EDIT 2...
I found out why 06:sts is causing an issue and why. The description on the site for sts is "Start or restart time step of the simulation. New simulation always starts from sts=0. You can restart the simulation from the point you output the simulation results in dump folder". So in your grid.txt file, sts is a positive number (not 0), so the program thinks that it is picking up at the sts time on an existing simulation. So I guess the error now makes sense too. I should have noticed this earlier but didn't have time to dig into the documentation. Either way, awesome program and I am going to keep messing with it!
Last edited by JD8; 04-08-2021 at 09:21 PM.
Reason: new info
I was lucky enough to get a Canadian company named Creaform to do the CFD for my Catfish. They used the same program that's used by several F1 teams and needed a server farm for the results. That said, it seems like your setup gives much of the general data that you'd need to make aero decisions. Open top is definitely bad for aero. If I remember, it might be as high as 0.48 Cd in top-down form.
I was lucky enough to get a Canadian company named Creaform to do the CFD for my Catfish. They used the same program that's used by several F1 teams and needed a server farm for the results. That said, it seems like your setup gives much of the general data that you'd need to make aero decisions. Open top is definitely bad for aero. If I remember, it might be as high as 0.48 Cd in top-down form.
That is really cool, when I was in school and on the formula team the aero guys had really nice CFD software with perfect models of our car like what you are showing.
The flowsquare software is really cool but I don't know to use it well enough yet to do 3D models that would be needed to know the aero impact of hardtop vs soft-top vs top down. I really wish I had paid more attention to the aero work back when I was in school.
03-02-2021, 08:59 AM
Flowsquare: Baby's First CFD Software
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