Book Description

Summary: Approximate formulas for the computation of the momentum thicknesses of turbulent boundary layers on two-dimensional bodies, on bodies of revolution at zero angle of attack, and on the inner surfaces of round channels all in compressible flow are given in the form of integrals that can be conveniently computed. The formulas involve the assumptions that the momentum thickness may be computed by use of a boundary-layer velocity profile which is fixed and that skin-friction formulas for flat plates may be used in the computation of boundary-layer thicknesses in flow with pressure gradients. The effect of density changes on the ration of the displacement thickness to the momentum thickness of the boundary layer is taken into account. Use is made of the experimental finding that the skin-friction coefficient for turbulent flow is independent of Mach number. The computations indicated that the effect of density changes on the momentum thickness in flows with pressure gradients is small for subsonic flows.