Frank Denys

Stellenbosch University | SUN · Department of Civil Engineering

Piano key weirs (PKWs) are nonlinear hydraulic structures that exhibit unsteady hydraulic phenomena. A study incorporating both physical and numerical modeling was undertaken to identify instabilities that are generated by flow. Several excitations were identified and a portion of their nature is characterized in this paper. These include a system...

This thesis considers the transient behaviour of piano key weirs (PKW) from a hydrodynamic and structural perspective. Their geometry makes them very rigid structures, however, there are thinner components of a PKW which may be prone to the onset of vibrations, specifically fluid or flow induced vibrations (FIV). Such vibrations, if strong enough a...

Piano Key Weirs generate complex flow patterns in their vicinity. These patterns are not only variant in space but also fluctuate over time. Time variant dynamics in the inlet key originate from the presence of separation bubbles which form at the entrance edge to the inlet key. This turbulent bubble periodically sheds vortices which cause regular...

The floodplain of a river forms a close relationship with the stream that created it. Not only does the river influence the characteristics of the floodplain, the floodplain can also very easily influence its river, as is evidenced by examples such as the Huang He River in China and the Columbia River in Canada. These two cases clearly indicate tha...