نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه مهندسی عمران، دانشکده مهندسی، دانشگاه ارومیه، ارومیه، ایران
2 گروه مهندسی عمران-آب و سازههای هیدرولیکی، دانشکده فنی، دانشگاه ارومیه، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Predicting and controlling the scour depth downstream of grade-control structures is one of the crucial hydraulics points in preventing riverbed erosion. The present research examines the influence of tailwater depth and longitudinal bed slopes at the downstream scouring depth of those structures by means of experimental settings. The experiments were conducted under the various tailwater depth conditions, including free tailwater e.g. 1.5 and 2 times of a free tailwater epth. The conditions were tested on three distinct longitudinal bed slopes: 0.05%, 0.2%, and 0.4%. Various flow rates were then introduced, necessary data were taken, and the hydraulic phenomena were studied. The results indicates that as the tailwater depth increases while maintaining a constant slope of the riverbed, the dimensions of the scour hole decreases. Establishing conditions for the maximum tailwater depth across various flow discharges resulted, on average, by 25% reduction in scouring depth downstream end of the structure. Conversely, by increasing the longitudinal bed slopes at a constant discharge and a related tailwater depth led to an increase in the dimensions of the scour hole. Specifically, when the bed slope increases from 0.05% to 0.4% under free tailwater conditions, the scour depth increases by 10.4%. Herein, a new relationship was developed based on the effective parameters to estimate the maximum scour depth for a grade-control structure. The correlation results demonstrated that this relationship yields accurate predictions with a high degree of reliability.
کلیدواژهها [English]
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