Abstract: On the basis of the experimental data measured with a LDA system, vertical velocity distributions are well compared for negative and positive gradient of slopes in different hydraulic conditions in an open channel. It’s concluded as follows: With Froude number increase, Karman constant decrease. A unified formula to describe velocity distribution in adverse slope is proposed and well testified.Viscous sublayer thickness and buffer layer scope in adverse slope are both bigger than those in slope. The authors draw some valuable conclusions and provide some references for the further study about hydraulic characteristics in adverse slope.

Key words: open channel, adverse slopen, on-uniform flow, velocity distribution