Phase relationships between velocity, wall pressure, and wall shear stress in a forced turbulent boundary layer

摘要

A large scale spatio-temporally periodic disturbance was excited in a turbulent boundaryudlayer via a wall-actuated dynamic roughness. Streamwise velocity, wall pressure, and directudwall shear stress measurements were made with a hot wire, pressure microphone, and audmicro-scale differential capacitive sensor, respectively. Phase-averaged fields for the threeudquantities were calculated and analyzed. A phase calibration between the various sensorsudwas performed with an acoustic plane wave tube over a range of operating conditionsudto validate a direct phase comparison between the respective quantities. Results suggestudencouraging agreement between the phase of the wall shear stress and velocity near the wall;udhowever, more refined velocity measurements are needed to make quantitative comparisonsudto the wall pressure. Overall, this work highlights the potential for wall-based control withudapplications towards reducing turbulent drag.