Author(s): S. Kouchakzadeh; A. P. Rizi
Linked Author(s): Salah Kouchakzadeh
Keywords: Discharge measurment; Brink ratio; Critical depth; Spatially varied flow
Abstract: Since the flow at free overfall is a self-calibrated, it has been extensively studied and used for flow measurement by many researchers. Different channel geometries, and super and sub critical flow regimes were considered previously. However, the influence of lateral inflow along the channel has not been studied yet. This research was conducted to investigate the discharge-end depth relationship in circular pipe carrying spatially varied flow with increasing discharge. Comparison between manometer readings and direct depth measurements at the brink confirmed the deviation of the pressure distribution from the hydrostatic one. The observed brink ratios, however, were higher than those obtained for constant discharge. The deviation were attributed to the transverse velocity distribution, which affects this type of flow greatly. Since a unique velocity correction factor could not practically be determined, based on the available experimental data a relationship between the brink flow and the critical flow depth is introduced which provide a reasonable estimate of the discharge in spatially varied flow condition.
Year: 2003