Hi @AnetaNovak,
I just had a quick look at your simulation, and the first thing I noticed is that there are no boundary layers in your geometry (you’ll need to split your geometry into different PIDs in order for the layer inflation to work). That could be one of the reasons you are not getting higher values for downforce.
I would also make the domain wider and have the cells more of a cubic shape with square faces instead of rectangular.
You can follow the Formula Student workshops to get a good quality simulation setup Step-by-Step Tutorial: Homework of Session 2
Cheers,
Pablo.