شبیه‌سازی با روش پیچک بزرگ لایة آمیخته شمال دریای عربی متأثر از شکست موج و گردش لانگمویر ناشی از مونسون تابستانی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری، دانشکده علوم وفنون دریایی، دانشگاه هرمزگان، بندرعباس، ایران

2 دانشکده علوم وفنون دریایی، دانشگاه هرمزگان، بندرعباس، ایران

3 استاد، گروه فیزیک، دانشکده علوم پایه، دانشگاه اصفهان، اصفهان، ایران

4 دانشکده علوم و فنون دریایی، دانشگاه هرمزگان

چکیده

در این پژوهش، شبیه‌سازی با روش پیچک بزرگ لایۀ آمیختة شمال دریای عربی با استفاده از مدل عددی پالم در شرایط سهیم بودن یا نبودن پدیده‌های شکست موج و گردش لانگمویر ناشی از باد مونسون تابستانی انجام شده است. ابعاد افقی این مقاله در افق 300 متر در 300 متر، عمق شبیه‌سازی شده 80 متر و فاصلة شبکه در هر سه جهت برابر با 25/1 متر است. به‌منظور اعمال اثر باد جنوب غربی، شار اندازه حرکت ناشی از باد در هر دو راستای   و  تعریف شده است. با توجه به هدف اصلی مقاله، به‌جای تلاش برای شبیه‌سازی شکست موج، با اعمال نوسانات تصادفی در سطح دریا، تأثیرات شکست موج بر لایة سطحی دریا در نظر گرفته شد. نتایج تحقیق نشان می‌دهد که شکست موج فقط بر اعماق نزدیک به سطح دریا (کم‌تر از 5 متر) تأثیرگذار است؛ حال آن‌که باریکه‌های به وجود آمده از گردش لانگمویر تا اعماق زیادی که مرتبه‌ای از طول‌موج در نظر گرفته شده است، نقش ایفا می‌کنند. همچنین این نتیجه حاصل شد که تلفیق هر دو پدیدة شکست موج و گردش لانگمویر موجب کاهش اندک انرژی جنبشی تلاطمی می‌شود که این امر می‌تواند از تأثیراختلالی شکست موج بر میدان سرعت به وجود آمده از نیروی تاو در سطح ناشی شده باشد. بااین‌وجود، برخلاف مطالعات پیشین، در هیچ عمقی اثر برش سرعت به‌عنوان عاملی تعیین‌کننده در بزرگی TKE به‌حساب نیامد.

کلیدواژه‌ها


عنوان مقاله [English]

Large Eddy Simulation of Ocean Mixed Layer of the Northern Arabian Sea Influenced by Wave Breaking and Langmuir Circulation

نویسندگان [English]

  • Iman Mehraby Dastenay 1
  • Hossein Malakooti 2
  • Smaeyl Hassanzadeh 3
  • Maryam Rahbani 4
1 Ph.D.c., Department of Marine science and technology, University of Hormozgan, Bandar Abbas, Iran
2 Department of Marine science and technology, University of Hormozgan, Bandar Abbas, Iran
3 Professor, Department of Physics, Faculty of Sciences, University of Isfahan, Isfahan, Iran
4 Department of Marine Science and Technology, University of Hormozgan
چکیده [English]

In this research, LES of ocean mixed layer of the north of Arabian Sea is conducted using PALM (Paralyzed Large Eddy Simulation) model experiments with or without the contribution of wave breaking and Langmuir circulation formed by summer monsoon. Unlike previous studies, wind induced momentum flux is defined in both x and y direction to apply SW wind. According to the main purpose of this work, the effects of wave breaking on the mixed layer is produced by defining random fluctuations on the sea surface, instead of trying to simulate wave breaking. Results showed wave breaking only affects the sea surface, less than 5 m; meanwhile, strips of Langmuir circulation are effective until a depth which is an order of the wavelength. Although, it was found that combining both effects of wave breaking and Langmuir circulation cause a slight decrease of Turbulent Kinetic Energy which can be caused by the distortion effect of wave breaking on the velocity field. Hence, unlike previous studies, the effect of velocity shear don’t play an important role in the magnitude of TKE.

کلیدواژه‌ها [English]

  • Turbulence
  • Large Eddy Simulation
  • PALM numerical model
  • Ocean Mixed Layer
  • Arabian Sea
  • Indian Monsoon
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