Measurements in a Turbulent Channel Flow by Means of an LDV Profile Sensor

Abstract

Spatially and temporally resolved velocity measurements in wall-bounded turbulent flows remain a challenge. Contrary to classical laser Doppler velocimetry (LDV) measurements, the laser Doppler velocity profile sensor (LDV-PS) allows the combined measurement of tracer particle position and velocity, which makes it a promising tool. To assess its feasibil- ity a commercial LDV-PS is employed in a turbulent channel flow at Re𝜏� = 350. Addition- ally, the measurement and signal-processing accuracies of velocity and location are evalu- ated 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 simula- tions. 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.