Gate-Opening Criteria for Generating Dam-Break Waves

Abstract

Dam-break waves are commonly used throughout the field of hydraulic engineering. Given the availability of several well-developed analytical solutions, as well as the relative ease with which they can be implemented as a numerical or physical boundary condition, dam-break waves have been used to examine various phenomena. This study employs a smoothed particle hydrodynamics (SPH) model to examine the influence of the gate opening on characteristics of the wave propagation. First, the model was extensively validated using experimental results from tests which employed swing and lift gates. Generally, any dam-break gate should open or be removed as fast as possible to allow the formation of a perfect dam break wave. However, cost-benefit considerations and technical design constraints, particularly for gates fitted on large-scale test facilities, result in less than instantaneous gate motions because the complexity and associated cost of the gate increases exponentially with increasing drive capacity. Larger gate weights installed in wide flumes require an improved understanding of the errors involved with slower opening times of both types of gate mechanisms. The study found that the influence of the gate opening time decreased with time elapsed from impounded water release, as well as with the downstream distance from the gate. The study also provides an estimate of the errors associated with the gate opening time to help engineers and researchers in the process of planning to generate such waves.