Fundamental Studies of Turbulent Boundary Layers with Injection or Suction through Porous Wall : 1st Report, Analysis of Turbulent Boundary Layers on Flat Plate with Injection

Abstract

This report presents the results of a basic research into turbulent boundary layers with injection. The research was conducted solely from considerations of fluid dynamics. It is intended to solve technical problems concerned with a sweat cooling system for gas turbine blades. In the first stage, a theoretical formula for velocity profile in a turbulent inner layer without injection was formed from a basic equation of motion by applying to it the Prandtl's mixing length theory. Separately from this, a turbulent outer layer along a flat plate is understood as one which is featured by the phenomenon of intermittency. Then, the intermittency theory has been amplified to substantiate that the phenomenon in the outer layer can be solved by statistic means. In the next stage, the same theory has been utilized to explain the whole region of turbulent boundary layers with injection. In addition, correlations among factors, which symbolize the velocity profile for turbulent boundary layers, have been found from experimental values. Finally it was proved that the theoretical velocity profile and the mean skin friction for turbulent boundary layers can be calculated simply by using correlative and momentum equations.