Experimental investigation of a turbulent boundary layer subject to an adverse pressure gradient at Re-theta up to 10000 using large-scale and long-range microscopic particle imaging

Abstract

We present an experimental investigation and data analysis of a turbulent boundary layer flow at a significant adverse pressure gradient for two Reynolds numbers Re-theta=6200 and Re-theta=8000. We perform detailed multi-resolution measurements by combining large-scale and long-range microscopic particle imaging. We investigate scaling laws for the mean velocity and for the total shear stress in the inner layer. In the inner part of the inner layer the mean velocity can be fitted by a log-law. In the outer part a modified log-law provides a good fit, which depends on the pressure gradient parameter and on a parameter for the mean inertial effects. Emphasis is on the Reynolds number effects on the mean velocity and shear stress.