بررسی نوسان مانع با وجود مانع ثابت در بالادست کانال روباز با استفاده از مدل فیزیکی

نویسندگان

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

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

چکیده

سازه­های آبی، در برخی مواقع موانعی در مسیر حرکت آب هستند که باعث ایجاد گردابه­های نوسانی در پایین­دست موانع می­شود. این گردابه­ها نیروهای نوسانی به مانع وارد کرده و پایداری سازه را دچار مشکل می­نماید. در سال­های اخیر از این پدیده در جهت تولید انرژی پاک استفاده می­شود. در تحقیق حاضر نوسان مانع با وجود مانع ثابت در بالادست مورد بررسی قرار گرفته است. آزمایش­ها با استفاده از مانع مثلثی در دبی­های متغیر با فواصل مختلف مانع در بالادست صورت پذیرفت. هدف اصلی این تحقیق بررسی اثر پارامترهای سرعت و فاصله مانع بالادست بر میزان فرکانس نوسانات می­باشد. با تحلیل ابعادی، پارامترهای بی­بعد عدد استروهال، عدد رینولدز و نسبت فاصله به قطر به­دست آمد. نمودارهای مربوط به رابطه عدد رینولدز و نیز فاصله به قطر در برابر اعداد استروهال ترسیم شدند. در پایان با استفاده از تجزیه و تحلیل داده­ها و نرم­افزار SPSS20 رابطه­ای جدید جهت برآورد عدد استروهال ارائه شد. با صحت سنجی رابطه ارائه شده، پیش­بینی نسبتا خوب آن مورد تایید قرار گرفت.

کلیدواژه‌ها


عنوان مقاله [English]

Study of Obstacle Oscillation in the Presence of a Fix Upstream Obstacle, Using a Physical Model

نویسندگان [English]

  • MR Etminan 1
  • A Hafari 2
  • S Jalili 2
  • J Zahiri 2
1 M.Sc. Student of Water Structures., Dept. of Water Engin., Ramin Agriculture and Natural Resources University of Khuzestan, Iran
2 Assist. Prof., Dept. of Water Engin., Ramin Agriculture and Natural Resources University of Khuzestan, Iran
چکیده [English]

Hydraulic structures in some cases, cause to produce obstacles in path of the flow that create oscillating vortices in downstream of the obstacles. Vortices produce oscillating forces to the obstacle that are harmful for the stability of structure. In recent years this phenomenon is used to create clean energy. In this study, oscillation of an obstacle in the presence of a fixed obstacle at the upstream was examined. The experiments on triangular block were carried out under varying discharge and different upstream distances. The main objective of this study was to investigate the effect of parameters of velocity and upstream obstacle distance on the oscillation frequency. Using dimensional analysis, the dimensionless parameters of Strouhal number, Reynolds number and ratio of distance to diameter were obtained. The charts of the relationship of the Reynolds number and also the ratio of distance to diameter vs. the Strouhal numbers were plotted. Finally, a new relationship was presented using data analysis and spss20 software to estimate the Strouhal number. Verifying the proposed relation, confirmed a fairly good prediction of this relation.

کلیدواژه‌ها [English]

  • Obstacle
  • Oscillation
  • Physical model
  • Reynolds number
  • Strouhal number
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