用平均速度剖面法测量壁湍流摩擦阻力

用IFA300恒温热线风速仪精细测量风洞中不同雷诺数流动条件下的平板湍流边界层近壁区域对数律平均速度剖面．利用平板湍流边界层近壁区域的对数律平均速度剖面与壁面摩擦速度、流体黏性系数等内尺度物理量的关系和壁面摩擦速度与壁面摩擦切应力的关系，在准确测量平板湍流边界层近壁区域对数律平均速度剖面的基础上，测量平板湍流边界层的壁面摩擦阻力．实现了平板湍流边界层壁面摩擦阻力的无干扰或微小干扰测量．该种方法操作简便，不需要在流场中安装测力天平、传感器等复杂的测量装置，不需要对湍流边界层的壁面进行破坏，不会影响湍流边界层壁面附近区域原有的流场条件，是一种切实可行的测量平板湍流边界层壁面摩擦阻力的简便方法．

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

On the basis of finely measured logarithmic mean-velocity profile in the near wall region of turbulent boundary layer over a flat plate in a wind tunnel using hot-wire anemometer of model IFA-300, we calculate the skin friction velocity according to the relationship between inner-scale physical parameters of logarithmic mean-velocity profile in the near wall region of turbulent boundary layer, such as mean velocity, skin friction velocity and fluid dynamics viscosity, and the relationship between skin friction velocity and skin friction drag. The skin friction measurement in a turbulent boundary layer is achieved by non-perturbed or micro-perturbed technique using logarithmic mean-velocity profile method. The present experimental method is simple, cheap and precise 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, the original flow condition in the near wall region of turbulent boundary layer is not disturbed. With its high automatic level and reliable experiment results, the mean-velocity profile method enjoys high efficiency and precision, for the measurement of skin friction drag-in turbulent boundary layer.