نوع مقاله: مقاله پژوهشی

نویسندگان

1 کارشناسی ارشد دانشکده مهندسی دریا، دانشگاه صنعتی امیرکبیر

2 دانشیار دانشکده مهندسی دریا، دانشگاه صنعتی امیرکبیر

چکیده

موجشکنهای حفره دار نسل جدیدتر موج شکنهای قائم هستند که در آنها مشکل انعکاس امواج و نیروهای زیاد وارد بر سازه تا حد زیادی حل شده است. در این مقاله به بررسی اثر شکل حفره‌های موجشکن حفره دار قائم بر مقدار ضریب انعکاس تحت اثر امواج تنهای برخوردی به روش عددی پرداخته شده است. موجشکن قائم مورد بررسی دارای صفحه ی تک و دوبل با چهار شکل حفره و چهار مقدار درصد بازشدگی مختلف صفحه ی روبرویی است. شبیه‌سازی این موجشکن در حالت سه‌بعدی به روش حجم محدود در نرم افزار Flow-3D انجام گردید. برای مدل‌سازی سطح آزاد جریان از مدل جزء حجم سیال (VOF) و به منظور محاسبه آشفتگی از مدل RNG-k-ε استفاده شد. نتایج نشان داد که در موجشکن با صفحات تک با افزایش مقدار تخلخل، به مقدار انعکاس موج نیز افزوده می‌شود بطوریکه صفحات با تخلخل 40% بیش از 90% موج تابشی را منعکس می‌کنند. همچنین مقدار ضریب انعکاس با افزایش نسبت بدون بعد B/L که در آن B عرض اتاقک موجگیر و L طول موج تابشی است به صورت نوسانی کم و زیاد می‌شود. همچنین موجشکن با صفحات دوبل نسبت به صفحات تک باعث استهلاک انرژی بیشتری در حدود 20 الی 25 درصد می‌شود.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Effect of hole shapes of perforated breakwaters on incident wave energy damping using numerical method

نویسندگان [English]

  • Mahmoud Ghasemi zadeh 1
  • M Ketabdari 2

1 Amirkabir University of Technology

چکیده [English]

Perforated breakwaters are newer generation of vertical breakwaters in which some how the problems of high wave reflection and forces exerted to the structure have been solved. In this paper the effect of hole shapes of vertical perforated breakwaters on reflection of solitary waves was investigated using numerical method. A single and double walls vertical breakwater with four different hole shapes and four different front wall porosity were considered. The breakwater was modeled in 3D using FVM method of FLOW-3D software. The free surface was modeled using VOF method while RNG-k-ε was used to model turbulent effect. The results show that in single wall breakwater as porosity increases the wave reflection increases as well so that a 40% porous wall reflects 90% of incident waves. Furthermore the reflection coefficient has a fluctuating nature as non- dimensional ratio of B/L increases (B is width of caisson and L is incident wave length). Moreover double wall breakwater is able to damp wave energy up to 20 to 25% greater than that of the single wall.

کلیدواژه‌ها [English]

  • Vertical perforated breakwater
  • solitary wave
  • Volume of fluid method
  • RNG turbulent model
  • Flow-3D software

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