B310 液晶を用いたせん断応力分布の瞬時計測法と非定常流への応用

抄録

A method for measuring the instantaneous shearstress distribution over a solid surface in a fluid flow is studied by using a surface-flow visualization technique with a shear-sensitive liquid-crystal coating. The color response of the liquid-crystal coating is calibrated against the various shearstress magnitudes and directions with an experimental test section of laminar channel flow. The measurement of instantaneous shear-stress distribution is carried out by using two color CCD cameras, which are situated side by side in stereoscopic arrangement. The color to shear stress transformation is conducted by analyzing the hue distribution of the visualized color image with the calibrated relationships between the hues from the two colour CCD cameras and the shearstress magnitude and direction. The usefulness of this technique was demonstrated by the measurement of shear-stress distribution around a circular cylinder over a surface under the decelerating flow condition.