تأثیر استغراق پرش هیدرولیکی بر نوسانات فشار کف حوضچه آرامش تیپ دو USBR

نوع مقاله: مقاله پژوهشی

چکیده

در تحقیق حاضر، نوسانات فشار جریان در کف حوضچه آرامش تیپ دو USBR در پایین­دست سرریز اوجی با استفاده از ترانسدیوسرهای فشار اندازه­گیری گردید. آزمایش­ها در یک فلوم آزمایشگاهی در شرایط مختلف جریان انجام گرفت. بعلاوه، میدان فشار در پرش هیدرولیکی مستغرق، به منظور کمک به درک بهتر فرآیند استهلاک انرژی و طراحی بهینه حوضچه­های آرامش مورد بررسی قرار گرفت. با استفاده از پارامترهای  بی‌بعد، تأثیر استغراق بر روی توزیع طولی فشار متوسط و شدت نوسانات فشار ارزیابی گردید. برداشت داده­های فشار برای اعداد فرود اولیه مختلف (Fr1) در محدوده 4/6 تا 3/8، و فاکتور استغراق (S) در محدوده 1 تا 4/1 انجام گردید. بر اساس تحلیل ابعادی، مقادیر ضریب شدت نوسانات فشار (p ) تابعی از پارامترهای Fr1، S و فاصله نسبی از ابتدای حوضچه (X/Y1) می­باشد. نتایج نشان داد که مقادیر حداکثر ضریب p در حوضچه تیپ دو نسبت به حوضچه­های صاف، حدود 30 درصد کاهش می­یابد. در ناحیه پایین­دست حوضچه آرامش (X/Y1>10)، متوسط مقادیر p در پرش­های مستغرق نسبت به پرش آزاد، حدود 25 درصد کاهش می­یابد.

کلیدواژه‌ها


عنوان مقاله [English]

Effect of Hydraulic Jump Submergence on the Bed Pressure Fluctuations of the USBR Type II Stilling Basin

چکیده [English]

In the present study, the flow pressure fluctuations have been measured on the bed of the USBR Type II stilling basin downstream of an Ogee spillway using pressure transducers. The experiments were carried out in a laboratory flume under different flow conditions. In addition, the pressure field in submerged hydraulic jumps was investigated to help better understanding the energy dissipation process and optimum designing the stilling basins. Using the dimensionless parameters, the submergence effect on the longitudinal distribution of the mean pressure and the pressure fluctuations intensity were evaluated. Pressure data acquisition was conducted for different incident Froude numbers (Fr1), ranged from 6.4 to 8.3, and submergence factors (S) in the range of 1 to 1.4. Based on the dimensional analysis, the values of the intensity coefficient of pressure fluctuations (p < /sub>) were a function of parameters of Fr1, S and the relative distance from the beginning of the basin (X/Y1). The results showed that the maximum values of p < /sub> coefficient for the Type II stilling basin decreased around 30% compared to the smooth basins. The mean values of p < /sub> in submerged jumps decreased around 25% compared to the free jumps at the downstream zone of the stilling basin (X/Y1>10).

کلیدواژه‌ها [English]

  • CʹP coefficient
  • Pressure transducer
  • Stilling basin
  • Submerged hydraulic jump
  • Submergence factor
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