Studying the Peak Discharge through a Planar Dam Breach

Abstract

Studying the flow through a dam breach is important because it is characterized by a great deal of uncertainty and can be associated with loss of lives and properties. In the present study, planar dam breach erosion due to overtopping is simulated using a three-dimensional (3D) computational fluid dynamics (CFD) model, FLOW-3D. The model parameters are calibrated by comparing the results of the dam surface elevations at different time instants with those of an earlier experimental study. Also, the results for maximum velocity and turbulence characteristics [turbulent kinetic energy (TKE), turbulence intensity (TI), and the excess shear stress (ESS)] are presented for the calibrated model. Sensitivity analysis of the parameters (dam material, d50, dam height, H0, downstream slope, s, width of the crest, b, and inlet discharge, Q) affecting the dam breach is performed to study the erosion rate and peak discharge through the breach section. Empirical equations for the peak breach discharge and erosion rate are presented using the simulated results. The study reveals that the dam material, inlet discharge, and dam downstream slope are among the most influential factors affecting the breaching process.