Turbulent flows in smooth-wall open channels with different slope

Abstract

One-dimensional and two-dimensional Laser Doppler Velocimeter (LDV) were used respectively to measure velocity of smooth-wall open channel flows with channel bed slopes varying between 0.25% and 3%. Turbulent flows were all supercritical with Froude numbers varying from 1.5 to 3.5 and Reynolds number having a magnitude of 105. Using 1-D LDV the law of the wall and the law of the wake were examined and the von Karman constant K was verified to be 0.4 universally, while the integral constant A might change with distance from the side wall. The law of the wake exists clearly with a wake strength Π of about 0.3. Moreover, from the 2-D LDV measurements, the influence of channel slopes on the turbulent characteristics were fully investigated.