Measurements in a turbulent channel flow bymeans of an LDV profile sensor

For the development of flow control techniques in wall-bounded turbulent flows, precise measurements of the flow in the proximity of the wall are essential. A laser Doppler velocity profile-sensor (LDV-PS) allows the combined measurement of tracer particle positions and velocities, which makes it a promising tool for flow measurements with high spatial resolution in flows with high velocity gradients. Therefore, the LDV-PS is employed in measurements of a turbulent channel flow at Reτ = 350. Additionally, LDV-PS measurement and signal-processing accuracies of velocity and location estimations are evaluated for various tracer-object sizes and velocities. On this basis, the turbulent channel flow measurements are evaluated and compared to reference data from direct numerical simulations. Thus, potentials of the LDV-PS are investigated for different regions of the flow, and various data processing routines as well as the experimental practice are discussed from an application perspective.