I compare NACA2415 and Clark Y airfoil for horizontal tail application for Re=0.2 million. Both the airfoil data from NACA and my 2D CFD simulation results give that the Clark Y airfoil has a larger Clmax than NACA2415 for Re=0.2 million (CFD data has good match with NACA data as typically in this case.). But when I do 3D CFD simulation for my AR=4, tapered ratio=0.5 horizontal tail, the simulations give that 3D NACA2415 H.T. give a more than 25% larger Clmax than 3D Clark Y H.T.. This conflicts with the 2D data.
CFD typically matches with experimental data well for lift prediction. So I think CFD reliability shall not be a problem. My guess explanation to this is: 3D flow is different than 2D and airfoil performance is very sensitive to the small change in flow. And this effect is just significant for the comparison between Clark Y and NACA2415 for my case.
Any experience or thought on this?
CFD typically matches with experimental data well for lift prediction. So I think CFD reliability shall not be a problem. My guess explanation to this is: 3D flow is different than 2D and airfoil performance is very sensitive to the small change in flow. And this effect is just significant for the comparison between Clark Y and NACA2415 for my case.
Any experience or thought on this?
