電気化学的計測手法を用いたせん断応力変動測定

抄録

Wall shear stress fluctuations are difficult to measure in the experiment, because it is hard to measure directly the velocity gradient close to a surface since the boundary layer thickness is so small that any measuring instrument will disturb the flow. However, a diffusion-controlled electrochemical reaction at small cathodes embedded in the wall can be applied to obtain the velocity gradient at the wall. In this paper, shear stress fluctuation measured by electrochemical method of turbulent pipe flow are analyzed and compared with LES through the power spectrum and probability density function. As well as use one low-pass filter to pick up the low frequency part for checking the effect of large-scale motion to the shear stress fluctuation, and the large-scale structures movement.