ملخص البحث :

: In this study, laboratory experiments were performed to evaluate the effects of the weir geometry of a Piano Key Weir (PKW) type B on thedischarge coefficient under free flow conditions. Experiments were conducted in a 15m long, 0.3m wide and 0.45m deep rectangular glass-walled flume.The experimental work includes testing of fourteen PKW models which results 290 tests to cover the effects of weir length and height, up-anddownstream key widths, upstream apex overhangs length, dam height and noses length on the weir flow discharge coefficient as well PKW with outletstepped key were considered in the analysis. Considering the experimental data, the dimensional analysis allowed the development of relations betweendischarge coefficient and the shape of the PKW and gave a good agreement. Experimental results showed that the most influential parameters for thetested PKW models are the Relative length L/W, Key widths W ⁄W, PKW Height B/P, and Overhangs length B ⁄B. The effectiveness of Piano Key Weirat low heads ratio (H/P = 0.25) is up to 400% relative to Creager weir at the same head.

ملخص البحث :

This study presents an experimental investigation to evaluate the effect of notch at sidewall of a Piano Key Weir (PKW) of type B and C on the discharge coefficient under free flow conditions. Model tests were conducted in a 15m long, 0.3m wide and 0.45m deep rectangular glass-walled flume. Eight physical models were prepared for both types: two traditional PKW type-B and C, and six notched models designed in similar dimensions to the traditional one. It was concluded that using staged PKW does not have a major effect on discharge capacity, water depth above the upstream apex (h1) for type B is greater than type C relative to its upstream piezometric head.