Pressure Measurments of Turbulent Boundary Layer Behavior over a Bump*

Experiments will be conducted in a subsonic turbulent boundary layer within a 15'' x 15'' x 12' test section. A 3D bump, inspired by the "Boeing bump" is selected for its tendency to induce flow separation and subsequent reattachement. The modified bump design features an aspect ratio (h/δ) between 1 and 1.4 at Reynolds numbers (Re_h) of 1.4x10⁴ to 1x10⁵. Time-resolved pressure measurements on the bump will be conducted at lower Re number and lower (h/δ) values compared to previous literature (Owens, 2021). Time-resolved measurements of surface pressure will be performed at two streamwise positions and four spanwise positions on the bump surface. Skin friction will be measured with IC2 sensors at two streamwise positions and four spanwise positions. Statistics and correlations between the pressure measurements and shear stress measurements at various positions will be calculated and presented. Furthermore, oil flow visualization will be implemented to detect the 3D topology to gain deeper understanding of the surface flow over the bump. This study aims to provide detailed measurements on the bump to analyze the impact of strong pressure gradients on turbulent boundary layer development across various Reynolds numbers and bump heights.