Momentum balance of a glass-plate patch in shallow flow.

Abstract

The resistance to flow of aqueous vegetation patches is a challenge to model due to their complex geometry and topological adaption under hydrodynamic loading. Patches not only influence the water level and mean velocities due to the drag they exert, but they also affect the turbulence and hence the processes such as the sediment deposition and erosion within and around the patch. Existing studies dealing with the interaction of flow and vegetation mostly measured the drag of individual plants or focused on the flow through and above homogeneous canopies. Studies of the flow around and within isolated patches are scarce and restricted to arrays of cylindrical elements. For leafy plants or surrogates there is only limited if any information and understanding of how the flow evolves through and around the plants. In this access project, the aim was to fill this gap via complementary physical lab-scale and numerical experiments of the flow through and around a surrogate leafy vegetation patch. The measurements were also performed around a real plant in the same flow configuration. Here, we focus on the momentum budget based on the measurements around the surrogate plant performed via stereoscopic particle image velocimetry (SPIV).