بررسی آزمایشگاهی و عددی آب‌شستگی اطراف گروه پایه کج با حضور شمع حفاظتی و طوق

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه تبریز

2 گروه مهندسی آب دانشگاه تبریز

چکیده

آب‌شستگی سالیان طولانی در علم هیدرولیک مورد مطالعه بوده است، با توجه به شرایط و پیچیدگی­‌های آن، همچنان مورد توجه محققین علم هیدرولیک قرار گرفته است. سازه­‌های هیدرولیکی که به صورت مانعی در برابر جریان آب قرار دارند الگوی جریان در نزدیکی خود را تغییر داده و به صورت موضعی باعث آب‌شستگی در اطراف سازه می­‌شوند. روش‌­های مختلفی برای کاهش آب‌شستگی موضعی اطراف پایه­‌ها بیان شده است. در این تحقیق برای کاهش آب‌شستگی موضعی اطراف سه پایه­ از گروه پایه کج به همراه شمع حفاظتی و طوق استفاده شده است. نتایج آزمایشگاهی نشان داد که با قرارگیری شمع حفاظتی در جلوی گروه پایه کج، تأثیر زاویه کج­شدگی پایه در کاهش آب‌شستگی کمتر است به‌­طوری­‌که اختلاف درصد کاهش آب‌شستگی برای پایه کج اول و کج دوم بین زاویه ۵ و ۱۵ درجه صفر بوده و برای پایه قائم 1/4درصد کاهش داشته است. استفاده از سه طوق به قطر b۴ در گروه پایه با فاصله بین پایه­‌های b۴ و وجود شمع حفاظتی در جلوی پایه کج اول به فاصله b۳ نسبت به فاصله b۲ به ترتیب کاهش 12/86، 21/85 و 12 درصدی عمق آب‌شستگی در جلوی پایه­‌ها را نشان می‌­دهد. نتایج مدل عددی نشان می‌دهد که استفاده از گروه پایه کج با فاصله بین پایه‌­های b۳ و با حضور شمع حفاظتی به فاصله b۲ از پایه اول نسبت به فاصله­‌های b و b۳ شدت تلاطم از مقدار 0/089 به مقدار 0/11 رسیده است.  

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental and numerical investigation of scour around inclined pier group with sacrificial pile and collar

نویسندگان [English]

  • Fatemeh Jafari 1
  • akram abbaspour 1
  • Hadi Arvanaghi 2
  • Ali Hosseinzade-Dalir 1
1 Tabriz University
2 Water Engineering Department, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
چکیده [English]

The scour has been studied in hydraulic science for many years; due to its complexity, it has been the attention of hydraulic scientists. Hydraulic structures are situated as an obstacle in front of water flow that changed the flow pattern in their vicinity and causing the local scour around the structure. There are various methods to reduce local scour around the pier. In this research, sacrificial pile and collar were used to reduce the local scour around the inclined pier group. The results show that using the sacrificial pile in front of the inclined pier group, the effect of the inclined pier angle on the reduction of the scour is lower. So the difference between the percentage of scour reduction for the first and second inclined piers with the angle of 5 and 15 degrees is zero and in vertical pier is 1.4%. The use of three collars with a diameter of 4b in pier group with the distance of 4b between piers and presence of sacrificial pile in front of the first inclined pier in the distance of 3b compared to 2b show a greater scour depth reduction in front of the piers. In the numerical model, the use of an inclined pier group with the distance of 3b between piers and sacrificial pile with the distance of 2b shows lower turbulence intensity compared to distances of b and 3b.

کلیدواژه‌ها [English]

  • collar
  • Inclination angle of the pier
  • Inclined pier group
  • Local scour
  • sacrificial pile
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