Lift
 

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.

Re: Lift
 

Run it transient.

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.

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?

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

Re: Lift
 

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