Local wall shear stress measurements with a thin plate submerged in the sublayer in wall turbulent flows

Abstract

A local wall shear stress measurement technique has been developed using a thin plate, referred to as a sublayer plate which is attached to the wall in the sublayer of a near-wall turbulent flow. The pressure difference between the leading and trailing edges of the plate is correlated to the known wall shear stress obtained in the fully developed turbulent channel flow. The universal calibration curve can be well represented in dimensionless form, and the sensitivity of the proposed method is as high as that of the sublayer fence, even if the sublayer fence is enveloped by the linear sublayer. The results of additional experiments prove that the sublayer plate has fairly good angular resolution in detecting the direction of the local wall shear stress vector.