Design of a Physical Model for Flow Deflectors at river Banks in a Laboratory Straight Channel Based on Scour Hole

Eco-friendly flow diversion structures called deflectors used for river restoration and aquatic habitat improvement, are installed on the river banks. The high velocity of river flow forms scour holes downstream of deflectors, which is a suitable pool for fish habitat. The present study investigates the geometric and hydraulic design of these structures considering holes and available laboratory data. Dimensional analysis indicated that the densimetric Froude number (Fa), the ratio of the water level deference upstream and downstream of the deflector to the deflector length (Ay/۱st), the ratio of the deflector opening to the channel width (b/B), the ratio of the deflector length to the channel width (۱st/B), the ratio of the longitudinal distance of pair deflectors to the channel width (L/B), and the angle of the deflector to the river's side wall (a) affect the depth (dse) and volume (se) of the scour hole. The results indicate a significant increase in scour depth with increasing ۱st/B and decreasing b/B. Also, at low flow depths, dse increases with increasing Ay/lst, and the hole depth increases with increasing L/B. The greatest value of dse occurs at an angle of ۹۰° and the greatest value of Vse occurs at an angle of ۱۱۰°.

کلیدواژه ها:

Scour ، Deflectors ، River ، Hydraulic Parameters ، Physical Model