Field Measurements of Three Dimensional Turbulent Structure in Curving River Flows and Evaluation of Bed Shear Stress

Abstract

Field measurements of three-dimensional turbulent structures were conducted in curving river streams at a point bar and an alternating bar. Clear secondary currents were observed in the curved sections, but they were transformed by shape effects of the cross section. The structures of mean velocity and turbulent quantities indicated characteristic properties according to the developing stage of flow due to the stream curvature. Evaluation methods of bed shear stress using the log-law, Reynolds stress and turbulence intensities were investigated.