بررسی سه بعدی گسترش آشفتگی جریان عبوری از آب شکن های مستقیم، T و L شکل در مجاری روباز با استفاده از مدل فیزیکی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد مهندسی سازه‌های آبی، دانشگاه کشاورزی و منابع طبیعی رامین خوزستان

2 استادیار گروه مهندسی آب، دانشگاه علوم کشاورزی و منابع طبیعی خوزستان

چکیده

آب­شکن سازه­ای است که در شرایط مختلف بازه­ی رودخانه­ها و با هدف حفاظت از سواحل رودخانه استفاده می­شود. در این مقاله به مطالعه­ی آزمایشگاهی ساختار جریان اطراف آب­شکن­های مستقیم، T و L شکل پرداخته شده است. بدین منظور هیدرودینامیک سه­بعدی جریان اطراف این آبشکن­ها به­صورت آزمایشگاهی و در یک کانال مستقیم با بستر صاف مورد مطالعه قرار گرفت. مؤلفه­های سرعت جریان در سه بعد در اطراف آب­شکن­ها به­وسیله سرعت­سنج سه­بعدی ADV اندازه­گیری شد. نتایج نشان می­دهد نقطه جدایی جریان به فاصله­ی 2 برابر طول آب­شکن­ها و در بالادست آب­شکن­ها می­باشد. حداکثر سرعت متوسط زمانی در امتداد صفحه جدایی جریان و در آبشکن مستقیم ایجاد می­شود. طول صفحه­ی برشی جریان در آب­شکن­های مستقیم، T شکل و L شکل به­ترتیب 10، 9/9 و 5/9 برابر طول جان آبشکن بوده و در نتیجه با افزایش طول بال آب­شکن گستره طولی گردابه پایین دست آبشکن کاهش می­یابد. حداکثر مؤلفه سرعت عمودی جریان در بالادست و دماغه آب­شکن­ها شکل گرفته و شدت آن در آب­شکن مستقیم بیشتر از دو آب­شکن دیگر در این مطالعه می­باشد. همچنین حداکثر انرژی جنبشی آشفتگی (TKE) در تراز 6/0 Z/H=و در امتداد لایه برشی و در آب­شکن مستقیم رخ می­دهد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Three-dimensional Study of Flow Turbulence Extension around Straight, T and L Shaped Groynes in Open Channles using Physical Model

نویسندگان [English]

  • Fatemeh Veisi 1
  • Ahmad Jafari 2
1 M. Sc. Department of Water Engineering, Ramin Agriculture and Natural Resources University of Khuzestan
2 Assistant Professor, Department of Water Engineering, Agricultural Sciences and Natural Resources University of Khuzestan
چکیده [English]

Rivers have long been considered as one of the most important sources of water supply. Flooding during flood events causes irreparable damage. Therefore, some methods such as the protection of river banks against erosion are considered to control the flood. One of the methods for protecting the rivers and controlling their erosion is the use of groynes. Groyne is a structure that uses rock, sand, etc. to   slow down the process of erosion and prevent ice-jamming, which in turn aids navigation . and generates suitable environmental conditions for aquatic organisms in different conditions and in different parts of the river. According to the importance of groynes, a detailed and three- dimensional study of turbulent flow and the intensity  of turbulence extension in these structures is of prime importance . In the present research, three- dimensional turbulent flow was completely studied using ADV advanced velocimeter in straight, L- and T- shaped groynes in a straight canal with a rigid substrate and 20% contraction of the groynes in the canal’s width by collecting numerous data points , and the turbulent extension  was studied in three- dimensions, which is one of the novel charactersistics of this research.

کلیدواژه‌ها [English]

  • Turbulent Flow
  • velocimeter
  • Vortex
  • River
  • Laboratory

مراجع

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علوم و مهندسی آبیاری
دوره 42، شماره 1
فروردین 1398
صفحه 15-29

فایل ها

سابقه مقاله

  • تاریخ دریافت: 16 اسفند 1395
  • تاریخ بازنگری: 01 خرداد 1396
  • تاریخ پذیرش: 02 خرداد 1396
  • تاریخ انتشار: 01 فروردین 1398

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