Direct measurement of bed shear stress using adjustable shear plate over a wide range of Froude numbers

The objective of this study is to extend reliability and applicability of the advanced measuring device for bottom shear stress introduced in the previous paper (Park et al., 2016) so that it could be deployed in the field. The high-speed open-channel flume used for the previous study has been renovated to accommodate even higher flow velocity (up to 6 m s−1). Then we adapted a non-intrusive velocity field measurement technique to such challenging flow conditions of interest. The specific experimental conditions required high degree of adaptation and subsequent development of analysis technique. The experimental results are used to reliably estimate bottom shear stress which is then compared to the measured value using the shear plate. It is shown that the shear plate can be applied to wide range of flow conditions by adjusting elastic shear modulus of the restoring mechanism.