On the Turbulent Boundary Layer with Pressure Rise and Fall

Abstract

This paper contains results from both, experiments and computations. The first part covers the experimental results of the velocity distributions of turbulent boundary layers in diverging and converging channels. To express the varying forms of these velocity distributions, the following empirical formula is proposed. u = u₀g(y/δ)｛m + (i-m)h(y/δ)｝, where u is the velocity at distance y from the surface of the wall, δ is the thickness of the boundary layer and u₀ is the velocity at y=δ or at the outer boundary of the layer. As the function of g(y/δ), the form of velocity distribution in a parallel wall channel or along a flat plate placed edgewise to the stream is taken. Then h(y/δ) is a function of y/δ, which is obtained from the experimental results and shown in .Figs. 6 and 10 in the original paper. Some considerations on the back flow in a diverging channel are suggested. As the result it was found that the back flow may occur on one side of the wall at a smaller diverging angle than is the case of back flow on both sides. the ratio of these angles being about 0.5. As applications of the above formula of the velocity distribution, problems of turbuient boundary layer of figure of revolution and approximate relations between the Reynolds' number and maximum lift coefficient of aerofoil section are treated, making use of Gruschwitz's empirical formula.