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Old   June 21, 2007, 12:07
Default Supersonic flow over flat plate
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Nikhil
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I tried to get the solution for the supersonic flow over a flat plate. After about 700 iterations, my horizontal velocity started turning negative towards the trailing edge and solution became imaginary.

Can anybody please suggest the mistake...
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Old   June 22, 2007, 02:47
Default Re: Supersonic flow over flat plate
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Ahmed
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Years ago, I solved this same problem, reduce cell size to around 0.01 mm in the flow direction (you can have more than that in the normal direction) and the corresponding time step
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Old   June 22, 2007, 07:51
Default Re: Supersonic flow over flat plate
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Mani
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>reduce cell size to around 0.01 mm

What if the flat plate is 0.02 mm long? Have you heard of non-dimensionalized variables?
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Old   June 22, 2007, 08:11
Default Re: Supersonic flow over flat plate
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Ahmed
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and you, have you ever spent 3 month writing a C-programme to solve this problem? and that was 15 years ago, learn to be modest?
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Old   May 20, 2013, 02:13
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sud
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I will try for it . My cell size is 1.42*10-7 . I have the same problem. Plate length is .01mm with 70*70 grid points.

The code seems to work good results for M=4 . for M>4 it fails and gives me imaginary solutions .

Does increase in Velocity has some effects on the grid ?

Should i increase the grid points to 80*80 ?
Any suggestion will be of great help .

Thanks
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Old   May 20, 2013, 06:03
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ufocfd
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Quote:
Originally Posted by Nikhil
;50337
I tried to get the solution for the supersonic flow over a flat plate. After about 700 iterations, my horizontal velocity started turning negative towards the trailing edge and solution became imaginary.

Can anybody please suggest the mistake...

Maybe you have a sub-sonic outlet boundary, and you need to change it to supersonic boundary type ?
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Old   May 20, 2013, 12:48
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The outlet is just an extrapolated value from the interior points . So i think thats not a problem
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