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Paul April 18, 2002 15:48

Dear All,

I'm working in calculation of external aerodynamics of automotiobiles. The main problem i have is, that the drag is brilliant but the lift is very poor. Im using k epsilon model. Are there any basic things i have to take care about. The surfacemesh is fine enough and quality is good. 5 boundary layers are used.

Joern Beilke April 18, 2002 22:20

Re: Lift
Run it transient.

paul 2 April 19, 2002 18:54

Re: Lift
Lift is probably the toughest aerodynamic coefficient to predict. Deciding what goes up and over and what goes down and under is not easy.

Make sure the y+ on the surface is within what k-e wants - 30 to 300??? And it would probably be better if the y+ was consistant over the entire surface of the vehicle. More cells between the bottom of the car/vehicle and the floor will also help.

Paul April 20, 2002 07:17

Re: Lift
This is what i thought about too, Do you have any experiences about the time scales? What timestep is common for such problems?

Paul April 20, 2002 07:22

Re: Lift
Do you have any experiences in using other turbulence models. I saw in Auto Technology Fluent is doing it with a Reynolds Stress Model. What do you think about that

Holidays April 22, 2002 06:52

Re: Lift
Try the SST model of Menter or a k-omega model...

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