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.

Run it transient.

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.

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

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

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