Physical model research on energy dissipation downstream of the new weirs of Denderleeuw in Belgium
Book Contribution - Book Chapter Conference Contribution
During the design of the new weir lock complex at Denderleeuw on the river Dender in Belgium Flanders Hydraulics Research performed physical model tests for the hydraulic design of the stilling basin of the new weirs. Three different downstream bottom levels as well as the presence of a stilling basin were tested for three different hydraulic conditions. The bottom level of the stilling basin was varied, as well as the slope of the end sill and the presence of dissipation blocks. The discharge, the upstream and downstream water level and the near bottom velocity downstream of the new weirs were measured. At the same time video cameras near the model recorded the flow pattern downstream of the weirs, from which by means of image processing techniques the location of the water line was determined. The physical model tests showed that a decrease of the downstream bottom level or a stilling basin are effective measures to ensure the formation of the hydraulic jump immediately downstream of the free falling nappe. The slope of the end sill of the stilling basin and the presence of energy dissipation blocks do not influence the location of the hydraulic jump, which remains located within the stilling basin. However, the near bottom velocity downstream of the stilling basin is increased by a steeper end sill and slightly reduced when energy dissipation blocks are present. Energy dissipation blocks also reduce the length of the hydraulic jump in the stilling basin.