SKIN FRICTION MEASUREMENT IN TURBULENT BOUNDARY LAYER BY MEAN VELOCITY PROFILE METHOD

On the basis of finely measured logarithmicmean-velocity profile in the near wall region of turbulent boundary layerover a flat plate in a wind tunnel using hot-wire anemometer of modelIFA-300, we calculate the skin friction velocity according to the relationshipbetween inner-scale physical parameters of logarithmic mean-velocity profilein the near wall region of turbulent boundary layer, such as mean velocity,skin friction velocity and fluid dynamics viscosity, and the relationshipbetween skin friction velocity and skin friction drag. The skin frictionmeasurement in a turbulent boundary layer is achieved by non-perturbed ormicro-perturbed technique using logarithmic mean-velocity profile method.The present experimental method is simple, cheap andprecise and without the need to use any complex equipment, such as sensors or balance, and to damage the surface of the plate. What is more, theoriginal flow condition in the near wall region of turbulent boundary layeris not disturbed. With its high automatic level and reliableexperiment results, the mean-velocity profile method enjoys high efficiency andprecision, for the measurement of skin friction drag in turbulentboundary layer.