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Old 03-09-2013, 04:38 PM   #105 (permalink)
aerohead
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cfd

Quote:
Originally Posted by Shortie771 View Post
Finally made a virtual kammback for the Del Sol, following the aerodynamic template. Sadly to my suprise though, it didn't seem to do anything for my aerodynamics The high point on my car is just too far forward (right at the top of the windshield it looks like). The air separates from the car before it even makes it far enough back for the kammback to be useful.

My car is supposed to have a CD of .35 stock. The software shows .48 (with or without kammback). Maybe I am doing something wrong.

All results are at 60 MPH with the exact same settings.

Template:


Flow Lines:


Top View:
It may require a university-grade CFD program to even approach the ability to develop meaningful Cds.The big-boys run super-computers to get 'close',then hours in the wind tunnel with clay modellers to dial in the final contours.
In the past,General Motor's Electronic Data Systems made programs available to university teams lacking wind tunnel facilities on campus,to help with their solar racer designs.
I contacted a state sales rep for one of the software companies which markets CFD software to schools.Knowing I was only an individual,they never returned my call.
I'm given to understand that the 'vehicle' must be defined within a 3-D AUTOCAD environment,with the exterior features represented by thousands of individual panels developed from the wire-frame model.
A system of sub-programs sets the mathematical foundation for the full Navier-Stokes Equation of spherical coordinate system which exceeds celestial mechanics in it's complexity for solution.
The wake structure must be known a priori in order to solve the equation.Not the reverse.
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