LXXII. Calculations concerning theoretical values of boundary-layer thickness and coefficients of friction and of heat transfer for steady two-dimensional laminar flow in an incompressible boundary-layer with mainstream velocity U ∝xmor U ∝xmor U ∝eαm

Summary 1. The boundary-layer thicknesses and coefficients of friction at the boundary, derived respectively from a numerical solution of the boundary layer equations and from Pohlhausen's adaptation of the momentum equation, are compared in the case of a steady two-dimensional laminar incompressible boundary-layer with mainstream velocity U ∝ xm or U ∝ U ∝ x m or U ∝ e αm (α>0). The results give an indication of the accuracy of Pohlhausen's method of treating the boundary-layer in those cases in which the assumption of similar velocity profiles in all sections of the boundary layer is strictly valid. Discrepancies are found to be small in the casee of negative pressure gradient.