مطالعه خصوصیات پرش هیدرولیکی مستغرق روی سطوح زبر و شیب معکوس

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه مهندسی آب، دانشکده کشاورزی، دانشگاه صنعتی اصفهان، اصفهان، ایران.

2 استاد، دانشگاه صنعتی اصفهان، تخصص: هیدرولیک

3 استاد، گروه مهندسی آب، دانشکده کشاورزی، دانشگاه صنعتی اصفهان، اصفهان، ایران.

4 استادیار، گروه مهندسی آب ، دانشکده کشاورزی، دانشگاه شیراز، شیراز، ایران.

چکیده

کنترل پرش هیدرولیکی برای کاهش خسارت وارده به ابنیه پایین‌دست از مسائل مورد توجه محققین است. هر چند تحقیقاتی بر روی کاربرد بستر زبر برای کنترل پرش مستغرق انجام شده است، اما مطالعه­ای بر روی کاربرد همزمان شیب معکوس همراه با زبری بستر و پله انتهایی انجام نگرفته است. در این پژوهش، بررسی خصوصیات پرش هیدرولیکی مستغرق در محدوده اعداد فرود اولیه 4 تا 10 و نسبت استغراق 1/0 تا 5/1 بر روی بستر با شیب معکوس، زبری سنگریزه­ای و ارتفاع پله انتهایی متفاوت انجام شد. نتایج نشان داد که در یک عدد فرود معین، طول پرش مستغرق و افت انرژی نسبی آن به ترتیب بیشتر و کمتر از این مشخصات برای پرش هیدرولیکی آزاد است. همچنین با افزایش نسبت استغراق اتلاف انرژی به‌طور متوسط 10 و طول پرش مستغرق در مقایسه با حالت کلاسیک آن 33 درصد کاهش نشان داد. همچنین ضخامت لایه مرزی بی­بعد در پرش مستغرق برابر با 37/0 به دست آمد. از سوی دیگر مقادیر ضریب نیروی برشی (ε) به‌طور متوسط 44/4 برابر حالت کلاسیک محاسبه شد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Study of characteristics of submerged hydraulic jump on bed roughness and adverse slopes

نویسندگان [English]

  • Nahid Pourabdollah 1
  • Manouchehr Heidarpour 2
  • Jahangir Abedi Koupai 3
  • Jahanshir Mohamadzadeh 4
1 PhD student, Water Engineering Department, College of Agriculture, Isfahan University of Technology ,Isfahan, Iran.
2 Professor, Water Engineering Department, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
3 Professor, Water Engineering Department, College of Agriculture, Isfahan University of Technology, Isfahan, Iran.
4 Assistant Professor, Water Engineering Department, College of Agriculture, Shiraz University, Iran.
چکیده [English]

Control of hydraulic jump to reduce damage to the structures of downstream is one of the issues of interest to researchers. Although several researches have been conducted on the application of rough bed to control submerged jump but, any study has not been published on the simultaneous application of the adverse slope, bed roughness and the positive step. In this research, the effect of different adverse slopes, bed roughness and positive step height were simultaneously investigated on characteristics of submerged hydraulic jump in Froude numbers from 4 to 10 and submerge ratio from 0.1 to 1.5. The results showed that in each special Froude number, the length of submerged jump and its relative energy loss are more and less than these specifications for free hydraulic jump; respectively. In addition to, with increasing the submerge ratio, the average energy loss and the submerged jump length decreased 10 and 33%; respectively as compare to the classical state. Also, the thickness of the dimensionless boundary layer of submerged jump was 0.37. On the other hand, the shear force coefficient (ε) was calculated 4.44 times more than the classic condition.

کلیدواژه‌ها [English]

  • Submerged jump
  • Submerged depth
  • Length of jump
  • Relative energy loss
  • Velocity profile

مراجع

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تحقیقات آب و خاک ایران
دوره 49، شماره 3
مرداد و شهریور
مرداد و شهریور 1397
صفحه 683-693

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