k形粗面上の乱流境界層の平均量特性

概要

論文の詳細を見る
Measurement of the mean flow quantities of turbulent boundary layer over two-dimensional spanwise groove with pitch ratio of 4,namely k-type rough wall has been made. The wall shear stress was determined from the direct measurement method with a floating element device. It is observed that the value of skin friction coefficient C_f is much larger than those of both the smooth wall and d-type rough wall flows, and is dependent of the relative roughness. Mean velocity and streamwise turbulent intensity profiles normalized with the outer variables are not similar, so the present k-type rough wall flow is not self-preserving. However, the logarithmic velocity profile having the same slope as that in the smooth wall flow is confirmed if the error in origin is considered. Roughness function correlates with u_rd_o/ν in a k-type rough wall, but the behavior of roughness function differs from that in the d-type rough wall. The tendency of wake strength vs. u_rδ/ν in a k-type rough wall is remarkably different from those in both a smooth wall and a d-type rough wall flows.
1998-03-25