Experimental Investigation of Submerged Vanes’ Shape effect on river-bend stability

In river meandering, when flow passes through a bend, reduction of flow velocity and rising hydrostatic pressure cause super elevation phenomena at outer side and reduction of water surface at inner-side of the bend. A helical motion results, causing erosion of the outer side of the bend. Installation of submerged vanes on the stream bed can reduce erosion of the outer bank significantly. In this study, to investigate the effect of shape on van effectiveness, a physical model with a rectangular-section canal of 110*0.73*0.35(m) dimensions with two 90° and 180° bends, has been constructed. Overall 28 experiments were performed, using three shapes of submerged vanes (flat, angled and curved). These vanes were installed on the bed of 90° and 180° bends of model with arrays of one, two and three vanes in parallel and zigzag patterns. Three curved vanes installed in parallel pattern on 90°-bend and zigzag pattern on 180-bend can be more effective in river bank protection.