Abstract
This report analyzes water surface disturbance like an oblique shock wave and a bottom transformation induced by pile-like construction on a steady supercritical flow. In the flow analysis, the two-dimensional shallow water flow theory was used, and the reflection of an oblique shock wave at the channel side wall and the distribution of velocity under the shock wave field were calculated using the ADI numerical calculation method. The water surface profiles and distributions of velocity of the oblique shock wave coincided fairly well with those observed in the fixed bed experiments.
The local scouring phenomenon at the front of the pile and non-equilibrium behavior of the sand movement were considered in the analysis of the bottom transformation. A bed load formula to describe the local scour was derived based on a reasonable estimation of the horseshoe vortex intensity and power model of bed load formula. Also, equations derived in our previous report were used to calculate non-equilibrium transport rate of bed load. The bottom transformations generated on alternative bars by the piles were calculated by use of the river bed analysis model incorporated the bed load formulae of the local scour and non-equilibrium of sand movement. The local scouring profile and the bottom transformation obtained by these analytical methods agreed well with those observed in the movable bed experiments.
