Based on n-power velocity and temperature profiles a method of computing various turbulent boundary layer thicknesses and shape factors affected by wall temperature and Prandtl number for fully developed subsonic gas flow over a flat plate is presented. Density variation in the boundary layer is given main consideration. Numerical computations include both heating and cooling of gas. Boundary layer thicknesses and shape factors are shown to be significantly affected by wall temperature and to a lesser degree by Prandtl number. An experiment is described which involved air flow up to 30 m/sec over a flat plate maintained at constant wall temperatures up to 250 C. Comparisons between theory and experiment are good.
Modeling for Actual Surface Roughness at Rarefied Gas Flow between Two Flat Plates