THREE INDIRECT METHODS FOR THE DRAG CHARACTERIZATION OF ARBITRARILY ROUGH SURFACES ON FLAT PLATES

Three indirect methods for characterizing the drag of an arbitrarily rough surface on a flat plate are derived or rederived from the similarity laws of turbulent shear flows. These are: (1) the well- known procedure using displacement thickness; (2) the probably not- so-well-known procedure using total drag; and (3) a proposed new procedure using only the freestream velocity and a local shear stress. The classical indirect procedure for pipe flow is also derived to show a commonality with the flat-plate methods.