Calculate Drag force for flat plate
 

Hi all,

I'm finding a drag force for a flat plate (very thin) in 2D that is perpendicular to free flow direction. In this case, the pressure force is much bigger than the viscous force, so I wonder if I can use wall y+ to judge the result ???

And what length I should use to calculate Reynolds number ? Because the flat plate is perpendicular to flow direction.

If the flat plate is parallel to free flow direction, I think wall y+ is applicable and I use the length of flat plate to calculate Reynolds number.

Thanks for reading my question.