بررسی آزمایشگاهی تاثیر طول آبشکن چوگانی بر آبشستگی در کانال مستقیم

نوع مقاله: مقاله پژوهشی

چکیده

یکی از روش­های محافظت و تثبیت سواحل رودخانه­ها استفاده از آبشکن می­باشد. آبشکن­ها با انحراف جریان از کناره­ها و هدایت آن به سمت محور اصلی رودخانه، باعث ته نشینی مواد رسوبی و تثبیت کناره رودخانه ها می­شود. آبشستگی در اطراف آبشکن و شکل دماغه آن از جمله پارامترهای مهم در مطالعات مهندسی رودخانه است. تغییر الگوی جریان در کناره ها، عامل موثری روی میزان آبشستگی موضعی در دماغه آبشکن می­باشد. در این مقاله با انجام مطالعات آزمایشگاهی به بررسی اثر طول آبشکن چوگانی (L) بر آبشستگی در کانال مستقیم پرداخته شده است. نتایج آزمایش­ها نشان می­دهد که تغییرات ابعاد چاله آبشستگی (شامل بیشینه عمق آبشستگی(ds)، طول چاله آبشستگی در بالادست و پایین دست آبشکن و بیشینه عرض آبشستگی) با طول آبشکن چوگانی نسبت مستقیم دارند. همچنین فاصله حفره آبشستگی از دیواره کانال در آبشکن چوگانی نسبت به آبشکن مستقیم بیشتر بوده است که سبب کاهش آبشستگی ساحل شده و به پایداری آبشکن کمک می­کند. با توجه به هدایت مناسب جریان به سمت پایین­دست، بیشینه میزان آبشستگی در آبشکن چوگانی نسبت به آبشکن مستقیم کمتر می­باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Experimental Investigation of Hockey groyne Length, on Scouring at Straight Channel

چکیده [English]

One of the regular methods for stabilizing and protecting the riverbanks is use of groyne structure. Groynes alter flow direction to the main axis of the river resulting sediment deposition and stabilization of river sides. Therefore, scour around the groyne and the effect of nose on scour are important parameters in river engineering. It should be noted that change of flow pattern in river side is an affective factor on the rate of scouring around the groyne nose. In this study, the effects of the hockey groyne length (L) on scour in straight channel has been investigated through experimental tests. The results showed that there was a direct relation between scour hole dimensions (including the maximum scour depth (ds), the length of scour hole in up and downstream and the maximum scour width) and hockey groyne length. Also, scour hole distance the from channel wall was longer in hockey groyne comparing to that in straight groyne which prevent from scour in river bank and stabilizing the groyne structure. Thus, maximum scour around the hockey groyne was less than that straight groyne around due to suitable flow direction to the downstream.

کلیدواژه‌ها [English]

  • Experimental study
  • Hockey groyne
  • Scour
  • Sediment transport
  • groyne length
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