Shear Stress Distribution at Channel Constrictions

A Comprehensive laboratory study, employing an appropriate range of flow Froude Number and contraction ratio, was undertaken for curvilinear and accelerating flow occuring against the advancing face and through the gap at end-dumped channel constrictions. Pertinent results on flow pattern, velocity distribution and boundary shear distribution, are reported and discussed. The locus of the shear maxima, which attains its highest point value on the advancing face of the constriction is observed to essentially overlap the path of the high velocity filament; a pattern that is similar to that found in a channel bend. Results show that which an increase in the contraction ratio, the corresponding increase in boundary shear over that in the uncontracted channel is exponential, although the increase in velocity is only nominal. A followup laboratory study on shear distribution at over-bank channel constrictions shows an identical trend.