1. The problem statement, all variables and given/known data I have a project to research the effect of surface roughness on wing performance. I found mostly that roughness leads to increased drag on a wing, however came across a website that briefly spoke about how recently researchers have observed how carefully selected roughness can suppress turbulent flow on the wing by delaying the transition point so that it is further back on the wing or even past the wing. However i am struggling to find actual research papers on this so does anyone know where to find more information on this, or could share any knowledge that you have on this subject yourself. Thanks!