Masaru Inada

Direct total skin-friction measurement of a flat plate in zero-pressure-gradient boundary layers

The total skin friction on a flat plate is directly measured by using a towing tank up to Reynolds number ReL 107 (or Rθ 104). Plates of 3.3 and 4.3 m in length are towed in still water, balancing the vertical weight by small flotation devices, and their drag force is measured by a highly sensitive load cell. We have developed a new technique to correct wave-making resistance, pressure resistance and drag on a turbulence simulator. When the measured total drag is converted into local drag, it is found that the local frictional resistance is about 6% smaller than that given by the Karman–Schoenherr formula. But it is consistent with the values obtained by the floating element technique, oil film interferometry and asymptotic evaluations.

Experimental Investigation of Turbulent Boundary Layer Over Smooth Flat Plate With Towing Tank: Attempt of Measurement of Frictional Stress

The purpose of this study is to evaluate the frictional resistance with sufficient accuracy and to evaluate the drag coefficient at high Reynolds numbers. We have measured the resistance of flat plate with using a towing tank. Correcting the wave-making resistance, pressure resistance, and drag on turbulence simulator, it is found that the measured frictional resistance is smaller than the Karman-Schoenherr formula. But it agrees with the values suggested by Osaka et. al and Osterlund et. al.Copyright