Hi,
I need help in calculation of EPA for street lights. From what I know we need to multiply Area and drag coefficient of the fixture.
How do we determine drag coefficient for different shape of fixtures?
material may have some play to it involving skin friction but usually it is not the case. the drag coefficient is mainly determined by the shape and not the material or thickness
"Material and wall thickness ?" ... negligible effect on drag.
sure, if you went to an practical thickness, like .005", the skins would vibrate something awfull; but for practical thicknesses (0.05") and ground level application (ie not supersonic) then no problem.
Material impact will almost certainly be negligible, so long as you keep it relatively smooth - unless you want to deliberately cause turbulence to energize the boundary layer.