Analytical solution of the depth‐averaged flow velocity in case of submerged rigid cylindrical vegetation

Abstract

[1] A new model for the depth-averaged velocity for flow in presence of submerged vegetation is developed. The model is based on a two-layer approach, where flow above and through the vegetation layer is described separately. Vegetation is treated as a homogeneous field of identical cylindrical stems, and the flow field is considered stationary and uniform. It is demonstrated that scaling considerations of the bulk flow field can be used to avoid complications associated with smaller scale flow processes and that still the behavior of depth-averaged flow over vegetation is described accurately. The derived scaling expression of the average flow field is simple in form, it follows fundamental laws of fluid flow, and it shows very good agreement with laboratory flume experiments. The new model can be used for quick evaluation of a river's hydraulic response in cases where vegetated floodplains are inundated.

Design of emergent and submerged rock-ramp fish passes

“…The l 0 value can be expressed experimentally using several approaches (Huthoff et al, 2007;Konings et al, 2012;Luhar et al, 2008;Nepf, 2012;Poggi et al, 2009). The present approach is a combination of these formulas in order to use a formula available for a large range of macro-roughness arrangement.…”

“…This model is adapted from one-dimensional vertical models developed for vegetation (Klopstra et al, 1997;Huthoff et al, 2007;Murphy and Nepf, 2007;King et al, 2012), and by analyzing experiments results obtained on a down-scale physical model. Vegetation models usually study the turbulent flow as a function of the geometry, being comparable with submerged rock-ramps.…”

A Semi-Analytical Model for the Hydraulic Resistance Due to Macro-Roughnesses of Varying Shapes and Densities

“…In parallel with this development, the double average has been used to obtain the hydraulic resistance of the bed, based on the geometric properties of the canopy. The hydraulic resistance is then estimated using empirical [11,12], analytical [13], or numerical computations [14,15]. These formulations require a turbulence closure relationship to ensure that they are universally valid [6,16].…”

Flow structure along the cross-section of an open-channel caused by patch of submerged vegetation

“…However, in vegetated flow, it is mostly affected by the vegetation drag because of the vegetation roughness which is dominant than river bed roughness [3]- [5]. There is an intricate interplay between vegetation and flow that causes vortices and swirling motions of various length scales [6]. Moreover, there are strong velocity gradients and important secondary currents in the flow through partially and/or submerged vegetated channels [1].…”

“…In these studies mainly three type vegetation considered which are submerged and fully vegetated bed [2], [6]- [12], submerged and partially vegetated bed along the channel [13] and emerged and partially vegetated bed along the channel [12], [14], [15].…”