تعیین ماتریس جرم افزوده‌ کشتی ‌هوایی با استفاده از روش المان مرزی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 مهندسی مکانیک، پژوهشگاه فضایی ایران

2 مهندسی مکانیک پژوهشگاه فضایی ایران

چکیده

در مقاله‌ حاضر ماتریس جرم افزوده‌ کشتی هوایی با استفاده از روش المان مرزی تعیین شده‌است. گسسته‌سازی معادلات حاکم بر روی شبکۀ مثلثی بر روی سطح جسم انجام شده‌است. شبکۀ محاسباتی بر روی سطح جسم با استفاده از نرم‌افزار گمبیت ایجاد شده و به‌صورت ورودی در کد المان مرزی نوشته شده به زبان فرترن به‌کار گرفته شده‌است. ابتدا به‌منظور صحه‌سنجی کد المان مرزی، ماتریس جرم افزوده‌ برای هندسه‌های متداول مانند کره و بیضی‌گون با نسبت قطر بزرگ به قطر کوچک 2 و 85/3 انجام شده‌است. نتایج حاصل از شبیه‌سازی المان مرزی کاملاً با مقادیر به‌دست آمده از حل تحلیلی تطابق دارند. سپس ماتریس جرم افزوده برای بدنۀ کشتی هوایی با دو پروفیل NPL و GNVR که از پرکاربردترین پروفیل‌ها در بدنۀ کشتی‌های هوایی است محاسبه شده‌است. در نهایت هندسۀ کامل کشتی هوایی به همراه مجموعۀ دم و سبد، با استفاده از دو پروفیل مختلف بدنه شبکه‌بندی شده‌است و ماتریس جرم افزوده برای کشتی هوایی در دو حالت به‌دست آمده‌است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Calculating the Added Mass Matrix of an Airship Using Boundary Element Method

نویسندگان [English]

  • Ali Jafarian 1
  • Sayed Mohammadreza Alavi Tabatabaei 1
  • Saeed Shakhesi 2
1 Iranian Space Research Center, Tehran, Iran.
2 Iranian Space Research Center, Tehran, Iran.
چکیده [English]

In this paper the boundary element method is used to calculate the added mass matrix of an airship. Here, the governing equations are desecrated on the triangular computational cells on the surface of the airship geometry. The computational grid cells are generated on the surface of the body using the Gambit software and inserted to the BEM Fortran code. First, in order to validate the numerical code, the added mass of a sphere and ellipsoid with two different fineness ratio (a/b=2, 3.85) is obtained and the results are compared with the analytical results. The BEM results are in a very good agreement with the analytical results. Then the BEM code is used to calculate the envelope added mass matrix with NPL and GNVR body profile which are two common body profiles in airships. Finally, the simulation is conducted for the whole airship with fins and gondola and the added mass matrix is obtained for two envelope profiles.

کلیدواژه‌ها [English]

  • Airship
  • Boundary Element Method
  • Added Mass
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