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  1. توسعه الگوریتم های نوین جهت کنترل توان و کاهش بار در توربین باد با دور متغیر
بررسی دینامیک حرکت چرخشی مدل زمین دولایه تحت تاثیر ژایر اقیانوسی
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بررسی دینامیک حرکت چرخشی مدل زمین دولایه تحت تاثیر ژایر اقیانوسی

رشت بهشت، حسین Rasht Behesht, Hossein

Investigation of the Rotational Dynamics of a Two-layer Earth Model under the in Uence of an Oceanic Gyre

Rasht Behesht, Hossein | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 47162 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Jalali, Mir Abbas
  7. Abstract:
  8. The planet earth has a variety of periodic motions in space, with periods varying from a day to thousands of years. The essence of studying the rotational motion of our planet is closely related to various phenomena such as, the long term variation of the earth’s climate, volcanic activities, ice ages, earth’s past dynamics, etc. furthermore, understanding the precise motion of the earth is an essential part of our astronomical observations. One of the many kinds of rotational motions, which has attracted many attentions is called Chandler wobble. Any irregularly shaped solid body rotating about some axis that is not aligned with its figure axis will wobble as it rotates. Although it has been under investigation for more than a century, its excitation mechanism has remained elusive. Since its discovery, many processes have been evaluated, without success, to determine whether or not they could be the excitation mechanism(s) of the Chandler wobble including atmospheric processes, continental water storage, core-mantle interactions and earthquakes. In the present study, with a Hamiltonian approach, we investigate the effects of the gyroscopic motion of the oceans on the wobbling motion of the earth and also study the feedbacks that these gyres receive from the earth’s motion. The main assumptions made in this work are, rigidity of the mantle, irrotational motion of the fluid core and most importantly a rigid disc instead of a fluid gyre. After derivation of the governing equations of motion, we will demonstrate that the gyroscopic motion of the oceans alone are not powerful enough to excite the chandler wobble but are capable of imposing small perturbations on the length of a day (LOD). Finally we will show that occurrence of a strong earthquake would change the rotation speed of an oceanic gyre
  9. Keywords:
  10. Hamiltonian Systems ; Chandler Wobble ; Oceanic Gyre ; Fluid Core ; Two-Layer Earth Model

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