تأثیر ایجاد موج‌های سطحی در رسوب‌شویی رسوبات تجمع یافته در بستر کانال‌های انتقال آب با مقطع مستطیلی

نویسندگان

چکیده

هدف از انجام این پژوهش بررسی تأثیر ایجاد موج‌های سطحی در جریان یکنواخت بر دبی بار بستر رسوبات تجمع یافته در بستر کانال با مقطع اولیه صلب مستطیلی است. پژوهش‌ها در یک فلوم آزمایشگاهی مستطیلی به‌ طول 10،‏ عرض 2‎/0 و ارتفاع 3‎/0 متر انجام شد. آزمایش‌های این پژوهش برای دو نوع ماسه با قطر متوسط 34‎/0 و 48‎/0 میلی‌متر و چگالی 67‎/2،‏ پنج تنش برشی متفاوت جریان یکنواخت (آستانه حرکت و مضارب 16‎/1،‏ 25‎/1،‏ 39‎/1،‏ 43‎/1 برابر آن برای دانه‌بندی اول،‏ و آستانه حرکت و مضرب‌ها 15‎/1،‏ 25‎/1،‏ 33‎/1،‏ 41‎/1 برابر آن برای دانه‌بندی دوم)،‏ دو ارتفاع موج (1 و 6‎/1 سانتی‌متر) و چهار سرعت موج مختلف انجام شد. نتایج آزمایش‌ها نشان داد که به‌ طور کلی ایجاد موج‌ها سبب افزایش دبی رسوب بستر خواهد شد. به ازای سایر پارامتر‌های آزمایشگاهی ثابت،‏ افزایش هر کدام از پارامترهای عدد استروهال (سرعت نسبی بی‌بعد)،‏ ارتفاع نسبی موج و تنش برشی جریان یکنواخت،‏ موجب افزایش مقدار دبی رسوب بار بستر خواهد شد. نتایج همچنان نشان داد که در محدوده آزمایش‌های انجام شده در این پژوهش،‏ ایجاد موج‌ها در جریان می‌تواند دبی رسوب بستر را در کانال صلب مستطیلی تا حدود 280% افزایش دهد.

کلیدواژه‌ها


عنوان مقاله [English]

The effect of creating the surface waves on dredging of deposited sediments in rectangular water conveyance channels

نویسندگان [English]

  • sajjad Veysi
  • mohammad Omid
  • Ali Vatankhah
چکیده [English]

The goal of this paper is, considering the effects of creating the surface waves in a uniform flow on the bed load transport rate of deposited sediment in a primal rigid rectangular channel. Experiments were carried out in a rectangular flume of 10m length, 0.2m width and 0.3m height. The experiments were conducted for two gradations of sediments with median diameters of 0.34 and 0.48 mm, specific weight of 2.67, for five bed shear stresses (initiation of motion and it’s multiplies of 1.16, 1.25, 1.39 and 1.43 for median diameter of 0.34 mm and initiation of motion and it’s multiplies of 1.15, 1.25, 1.33 and 1.41 for median diameter of 0.48 mm), two wave heights (1 and 1.6 cm) and four different wave velocities. The results showed that creating surface waves generally increases the bed load transport rate. Furthermore, it was observed that for a given experimental parameters, the bed load transport rate increases with Strouhal number, dimensionless wave height and bed shear stress. It can be concluded that creating artificial waves can increase the bed load transport rate in a rigid rectangular channel up to 280% compared to the no wave conditions.
The goal of this paper is, considering the effects of creating the surface waves in a uniform flow on the bed load transport rate of deposited sediment in a primal rigid rectangular channel. Experiments were carried out in a rectangular flume of 10m length, 0.2m width and 0.3m height. The experiments were conducted for two gradations of sediments with median diameters of 0.34 and 0.48 mm, specific weight of 2.67, for five bed shear stresses (initiation of motion and it’s multiplies of 1.16, 1.25, 1.39 and 1.43 for median diameter of 0.34 mm and initiation of motion and it’s multiplies of 1.15, 1.25, 1.33 and 1.41 for median diameter of 0.48 mm), two wave heights (1 and 1.6 cm) and four different wave velocities. The results showed that creating surface waves generally increases the bed load transport rate. Furthermore, it was observed that for a given experimental parameters, the bed load transport rate increases with Strouhal number, dimensionless wave height and bed shear stress. It can be concluded that creating artificial waves can increase the bed load transport rate in a rigid rectangular channel up to 280% compared to the no wave conditions.
The goal of this paper is, considering the effects of creating the surface waves in a uniform flow on the bed load transport rate of deposited sediment in a primal rigid rectangular channel. Experiments were carried out in a rectangular flume of 10m length, 0.2m width and 0.3m height. The experiments were conducted for two gradations of sediments with median diameters of 0.34 and 0.48 mm, specific weight of 2.67, for five bed shear stresses (initiation of motion and it’s multiplies of 1.16, 1.25, 1.39 and 1.43 for median diameter of 0.34 mm and initiation of motion and it’s multiplies of 1.15, 1.25, 1.33 and 1.41 for median diameter of 0.48 mm), two wave heights (1 and 1.6 cm) and four different wave velocities. The results showed that creating surface waves generally increases the bed load transport rate. Furthermore, it was observed that for a given experimental parameters, the bed load transport rate increases with Strouhal number, dimensionless wave height and bed shear stress. It can be concluded that creating artificial waves can increase the bed load transport rate in a rigid rectangular channel up to 280% compared to the no wave conditions.
The goal of this paper is, considering the effects of creating the surface waves in a uniform flow on the bed load transport rate of deposited sediment in a primal rigid rectangular channel. Experiments were carried out in a rectangular flume of 10m length, 0.2m width and 0.3m height. The experiments were conducted for two gradations of sediments with median diameters of 0.34 and 0.48 mm, specific weight of 2.67, for five bed shear stresses (initiation of motion and it’s multiplies of 1.16, 1.25, 1.39 and 1.43 for median diameter of 0.34 mm and initiation of motion and it’s multiplies of 1.15, 1.25, 1.33 and 1.41 for median diameter of 0.48 mm), two wave heights (1 and 1.6 cm) and four different wave velocities. The results showed that creating surface waves generally increases the bed load transport rate. Furthermore, it was observed that for a given experimental parameters, the bed load transport rate increases with Strouhal number, dimensionless wave height and bed shear stress. It can be concluded that creating artificial waves can increase the bed load transport rate in a rigid rectangular channel up to 280% compared to the no wave conditions.

کلیدواژه‌ها [English]

  • Bed shear stress-Wave-Rigid rectangular channel-Uniform flow.-Bed load-