Classification of flow patterns in rectangular shallow reservoirs

Abstract

This work focuses on the experimental classification of flow patterns in rectangular shallow reservoirs, including symmetric flows without any reattachment point to asymmetric flows with one reattachment point, two reattachment points, or two reattachment points and one detachment point. The median position and the natural variability of the reattachment lengths 2 of asymmetric flows were measured for forty geometric and hydraulic conditions. The effects of dimensionless flow depth, Froude number, lateral expansion ratio and dimensionless length on the median reattachment lengths were analyzed. A number of regression equations were proposed. For "high" dimensionless flow depths and a Froude number of 0.20, a shape parameter was proposed for predicting the transition between symmetric and asymmetric flows. The results of this study are useful knowledge for improving current methods to predict the trapping efficiency and the preferential regions of deposition in reservoirs.

Experimental study of velocity fields in rectangular shallow reservoirs

“…The authors refer to a non-dimensional shape parameter Dufresne et al (2010). For the tested hydraulic conditions, the authors report that for T < 4.09, the flow remains symmetric, while for T > 4.48, the flow is asymmetric, with a transition zone between the two limits, corresponding to "unstable" flow pattern.…”

“…Although previous papers have paved the way for the classification (Dewals et al 2008, Dufresne et al 2010, the authors are complemented for the detailed flow-field measurements conducted for a high number of reservoir geometries, complementing the previous observations based on Large Scale Particle Image Velocimetry (Dewals et al 2008).…”

Maximum energy dissipation to explain velocity fields in shallow reservoirs

“…assuming a plug flow); and therefore a detailed knowledge of the flow field developing in the reservoir is needed. It has been shown that this flow field is strongly influenced by the shape of the reservoir (Dufresne, Dewals, Erpicum, Archambeau, & Pirotton, 2010a;Kantoush, Bollaert, & Schleiss, 2008), the bottom roughness (Choufi, Kettab, & Schleiss, 2014) and the sediment load (Camnasio et al, 2013). In this study we focus on reservoirs with a relatively smooth bottom roughness without sediment loads.…”

Coupling between flow and sediment deposition in rectangular shallow reservoirs

“…According to recent research, complex flow fields with largescale horizontal vortices develop in such reservoirs despite their simple geometry (Dewals et al 2008, Dufresne et al 2010a, Camnasio et al 2011. In addition to symmetric jet flows, several asymmetric flow patterns were indeed observed in spite of the hydraulic and geometric symmetry of the setup.…”