An investigation of a separated equilibrium turbulent boundary layer

The experiment, carried out in a boundary layer tunnel, seeks to establish the existence of separated equilibrium flows and to extend previous studies of the family of equilibrium boundary layers into separated flow. The measurements are thought to be the first demonstration that equilibrium turbulent separated boundary layers can be realized experimentally. The principal data are obtained with a single-component laser Doppler anemometer using the photon correlation technique and incorporating frequency-shifting by Bragg cells. Measurements along the center-line of the wind tunnel are supplemented by checks of the spanwise variation in the boundary layer properties. Measurements are also made of wall and boundary layer static pressures. Shear stresses, not susceptible of measurement, are estimated on the basis of the equations of motion and are compared with values obtained near separation in attached equilibrium flow.