Author(s): Michele Trevisson; Gregory Ivey; Marco Ghisalberti
Linked Author(s): Michele Trevisson
Keywords: Roughness; Frontal density; Flow regimes; Obstacle wakes; Open channel flows
Abstract: Even though roughness is ubiquitous in environmental flows (e.g. vegetated river beds, urban canopies, etc.), a clear understanding of the flow regimes induced by the roughness morphology, i.e. its density and shape, is still missing. For arrays of cubes, Morris (1955) identified three flow regimes based on the flow patterns between subsequent roughness elements: isolated (for sparse roughness with non-interacting wakes), wake-interference (in the presence of wake-obstacle interaction), and skimming (for dense roughness with stable recirculation regions in the grooves). MacDonald (2016) found that flow patterns alone are insufficient to fully distinguish flow regimes, having observed the same flow patterns for wavy surfaces of different roughness densities. The transition between wake-interference and skimming flow is often associated with a peak in bed drag (Raupach, 1991), suggesting that a change in flow regimes may be a function of the dynamic parameter
Year: 2025