Identification of Pressure and Velocity Correction Coefficients along Block-stones Ramp

Along a non-uniform flow in a stream or river, the pressure, energy, and momentum coefficients tend to vary from section to section. These coefficients also tend to vary with the water depth and discharge. Although some researchers provided some values of these coefficients for special conditions, their spatial variability in accelerated flow has not been adequately investigated. To simplify calculations, the values of these coefficients are usually assumed to be constants. This implies that the cross-sectional velocity and pressure distributions do not change with space. Values of these constants are often regarded as unity, which implies that the velocity is uniformly distributed over the cross section while the pressure distribution is hydrostatic. However, effect of these coefficients on the solution of non-uniform flow equations is not well understood. In this study, a new simple method for computing the pressure, energy, and momentum correction coefficients from the water surface profile for accelerating flow over block stones ramp was developed. This method is based on the assumption that the water depth at the beginning of the ramp is equal to the critical depth. The study revealed that the maximum deviation in the pressure is at the ramp crest and decreases in the downstream direction until it reaches to uniform flow condition at some distance from the ramp crest. Values of energy correction coefficient and momentum correction coefficient are nearly constant at the ramp crest and increase by increasing the distance from the ramp crest. Along the ramp, the velocity correction coefficient increases by decreasing the discharge.