On the Mixture Length in the Turbulent Boundary Layer with a Pressure Gradient (1st Report)

Abstract

In order to get a more reliable knowledge on the mixture length in pressure flow, experiments of Nikuradse, Donch and Fage-Falkner are reanalized by the method of a modified momentum transfer theory. The results obtained are as follows. The slope of the mixture length at the wall surface is independent of the pressure gradient and takes the value 0.4. The form of it in the outer region of the boundary layer is, however, somewhat affected by the gradient nearly like Nikuradse's results. Universal constancy of the slope leads to the so called wall law of the velocity distribution and serves to determine the more precise value of the wall friction.