Abstract
Accelerating and decelerating flows, i. e., flows with the streamwise non-uniformity of bed boundary, are greatly affected by the pressure gradients. It is of both fundamental and practical importance to investigate the effects of various pressure gradient on the turbulent structures in open-channel flows in order that the statistical characteristics such as mean velocity, turbulence intensity and shear stress are largely different from the uniform open-channels and zero-pressure gradient boundary layers. Near-wall region which consists of viscous sublayer and buffer layer in open-channel flows over a sine-formed wavy bed was accurately measured by means of a two-component and fiber-optic laser Doppler anemometer (LDA); the effects of pressure gradient produced by such a bed shape and free-surface profile were discussed with respect to profiles of turbulence characteristics.
