مهندسی مکانیک مدرس

مهندسی مکانیک مدرس

ارزیابی پارامترهای هیدرودینامیکی در ارتعاش ناشی از گردابه سازه‌های استوانه‌ای با تکیه‌گاه غیرخطی

نوع مقاله : پژوهشی اصیل

نویسندگان
دانشگاه صنعتی خواجه نصیرالدین طوسی
چکیده
ارتعاش ناشی از گردابه پدیده‌ای مهم است که در سازه‌های فراساحلی رخ می‌دهد و می‌تواند باعث خستگی این سازه‌ها و آسیب به آن‌ها شود. مطالعات گذشته نشان می‌دهد که این سازه‌ها رفتاری پیچیده و گاهی غیرخطی از خود نشان می‌دهند. در این مطالعه، به‌منظور ارزیابی پارامترهای هیدرودینامیکی در این سیستم‌ها، از یک استوانه صلب با تکیه‌گاه غیرخطی استفاده شده است. میزان غیرخطی بودن تکیه‌گاه تغییر داده شده و تأثیر آن بر پارامترهای هیدرودینامیکی سیستم مورد بررسی قرار گرفته است. با حل هم‌زمان معادلات دوبعدی ناویر-استوکس با میانگین رینولدز و معادله حرکت استوانه، جابه‌جایی و سرعت استوانه به‌دست‌آمده است. ضرایب برآیی، پتانسیل و گردابه محاسبه شده و در نهایت عدد استروهال تعیین شده است. نتایج حاصل‌شده نشان می‌دهد که رفتار سیستم از دو شاخه تشکیل می‌شود. در شاخه 1 دامنه حرکت استوانه کوچک است اما در شاخه 2 دامنه حرکت آن چند برابر می‌شود. با افزایش میزان غیرخطی بودن تکیه‌گاه، محدوده شاخه 2 کوچک‌تر می‌شود و سرعت نوسان استوانه افزایش می­یابد. هم‌چنین افزایش میزان غیرخطی بودن تکیه­گاه موجب کاهش نیروی برآیی وارد بر استوانه و عدد استروهال می­شود.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

Evaluation of hydrodynamic parameters in vortex-induced vibration of cylindrical structures with nonlinear support

نویسندگان English

Saeed Asil Gharebaghi
Mohammad Shirzad
K. N. Toosi University of Technology
چکیده English

Vortex-induced vibration is a critical phenomenon that occurs in offshore structures and causes fatigue and damage to these structures. Previous studies show that these structures show complex and sometimes non-linear behavior. This study uses a rigid cylinder with non-linear support to evaluate the hydrodynamic parameters in these systems. The amount of non-linearity of the support has been changed, and its effect on the hydrodynamic parameters of the system has been investigated. The displacement and velocity of the cylinder were obtained by solving the two-dimensional Reynolds averaged Navier-Stokes and cylinder motion equations. The lift, potential, and vortex coefficients were calculated. Finally, the Strouhal number was determined. The results show that the system's behavior consists of two branches. In branch 1, the motion amplitude of the cylinder is small, but in branch 2, its amplitude is multiplied. By increasing the non-linearity of the support, the range of branch 2 becomes smaller, and the velocity of the cylinder oscillation increases. Raising the support non-linearity reduces the lift force and Strouhal number

کلیدواژه‌ها English

Vortex-Induced Vibration
Non-Linear Support
Hydrodynamics Parameters
Strouhal number
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