بررسی آزمایشگاهی آبشستگی پایین دست سرریز لابیرانت مستطیلی با دریچه

نوع مقاله: مقاله پژوهشی

نویسندگان

1 استادیار؛ گروه مهندسی آب، دانشکده کشاورزی، دانشگاه بوعلی سینا همدان، همدان، ایران

2 دانشجوی کارشناسی ارشد گروه مهندسی آب، دانشکده کشاورزی، دانشگاه بوعلی سینا همدان، همدان، ایران

چکیده

با توجه به کارایی مناسب سرریزهای لابیرنت، تحقیقات بسیاری در زمینة مزایا و کاربرد این سرریزها صورت گرفته است. این تحقیق به­منظور بررسی هیدرولیک جریان و تاثیر سازۀ ترکیبی سرریز- دریچه بر میزان آبشستگی در پایین­دست سازه، به­صورت آزمایشگاهی اجرا شده است. در این تحقیق 12 آزمایش در 3 دبی متفاوت 10، 15 و 20 لیتر بر ثانیه برای حالت جریان از روی سرریز و جریان همزمان از روی سرریز- دریچه برای دو مدل سرریز خطی و لابیرنت اجرا شده است. نتایج تحقیقات نشان می­دهد که در سرریز لابیرنت با تخلیۀ بیشتر انرژی در محل برخورد با کف­بند، امکان انتقال بیشتر رسوبات به پایین­دست کاهش می­یابد و ارتفاع موج ماسه در پایین­دست کف­بند بیشتر است. با افزایش فرود ذره برای عمق پایاب ثابت بیشینۀ عمق آبشستگی و طول گودال آبشستگی افزایش پیدا می­کند. در جریان همزمان از روی سرریز و دریچه، در سرریزهای لابیرنت و سرریزهای خطی بیشینۀ عمق آبشستگی و طول حفرۀ آبشستگی نسبت به جریان از روی سرریز افزایش پیدا می­کند. بیشینۀ عمق آبشستگی و طول حفرۀ آبشستگی با افزایش دبی افزایش می­یابد و مقدار آن در سرریزهای لابیرنت، نسبت به سرریز خطی، در تمام حالات کمتر است.

کلیدواژه‌ها


عنوان مقاله [English]

Study Downstream Scour of Rectangular Labyrinth Weir with Gate

نویسندگان [English]

  • saeed gohari 1
  • zahra kabiri 2
1 Hamedan-Bu-Ali Sina University-faculty of agriculture-department of water science engineering
2 bu Ali sina university
چکیده [English]

Labyrinth weirs can be used to increase outlet capacity for a given spillway crest elevation and length or to increase storage by raising the crest while maintaining spillway capacity. Downstream scour dimensions of spillway are important parameters in designing of this structures. By combining the spillway and the gate, two major problems of sedimentation on upstream of spillway and the accumulation of waste materials can be solved. In this study, totally 12 experiments were carried out in 3 different discharges, 10, 15 and 20 liters per second. In this study overflow and flow simultaneously from top of weir and gate for two linear and labyrinth spillway were explored. A layer sand with d50=1 mm and thickness of 15 cm were covered at downstream apron to make a mobile bed. Results showed that by increasing the particle Froude for a constant depth, the maximum scour depth and scour hole length increased. Also it was found that when the flow passed through the spillway and gate simultaneously, in both labyrinth and linear spillway, the maximum scour depth and scour hole length increased with respect to discharge. Transverse profiles at the maximum scour depth also showed that there was a relative symmetry in the case of a linear spillway without a gate, and in this case the bottom profile could be considered as two-dimensional. The maximum scour depth and scour hole length increased with increasing discharge, and its magnitude in labyrinth spillways, was less than that in linear spillways.

کلیدواژه‌ها [English]

  • Apron
  • Linear Spillway
  • Rectangular Labyrinth Spillway
  • Scour

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