TURBULENT OPEN-CHANNEL FLOW WITH UPWARD SEEPAGE

Measurements of turbulent open-channel flow subjected to an upward bed seepage were performed in a laboratory flume using a two-dimensional Acoustic Doppler Velocimeter and a minipropeller. The experimental res ults show that the boundary seepage affects the time-mean streamwise v elocity, the rms values of the velocity fluctuations, the Reynolds she ar stress and the bed shear stress in open-channel flow. Along the see page zone, the mean streamwise velocity increases much more in the sur face layer than that in the near-bed region, whereas the turbulent int ensities and Reynolds shear stress increase significantly in the near- bed region. The bed shear stress that was computed using the momentum integral equation shows a steady reduction with increasing upward seep age velocity.