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First International Symposium on Flutter and its Application (May 15-17, 2016. Mielparque-tokyo), Minato-ku, Tokyo, Japan, More or less, the objectives of the engineering are to find optimal solution for the design of the products. Classically the variational methods have been used to find the optimal design in the engineering fields. So many numerical solutions are based upon the variational methods or its similar approaches even if the variational principle does not exist. Variational principles in the fluid dynamics has not been established yet, while those in elasticity and plasticity and optimal control theory have been highly confirmed and applied to actual problems. In this presentation, the methods of calculus variations are reviewed in the fields of structure and elasticity, optimal control theory and fluid dynamics. Firstly the fields of elasticity and optimal control theory are briefly reviewed. The details of them are not discussed here. Focusing on the fluid dynamics, a process of deriving the Hamilton’s principle is shown toward the applications for fluid-structure interaction problems like flutter or other interdisciplinary problems in engineering. The principle of virtual work is applied to the governing equations with boundary conditions. The conservation laws of mass and energy as well as the geometrical boundary conditions are treated as subsidiary conditions. In the present approach, a new concept of substantial variations of the state variables is introduced in order to describe the transportation terms and subsidiary conditions in a simple manner. It is a classical approach but might be useful for the development of computer aided design tools for aeroelasticity system and its optimal design., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1630046041, レポート番号: JAXA-SP-16-008E

First International Symposium on Flutter and its Application (May 15-17, 2016. Mielparque-tokyo), Minato-ku, Tokyo, Japan, The Lifting Line Theory is based upon the fact that the local lift at a wing section depends not only on the local section angle of attack but also on the downwash induced by the tailing vortexes shed from the next segments of the wing. It predicts quantitatively the spanwise lift distributions of 3D wing, the induced drag and the load distribution of minimum- drag 3D wing. It is also well consistent with the momentum theory about 3D wing. There are two puzzles for the engineers in the aeronautics, especially for aeroelasticians and aerodynamicians in the world. (i) the collocation point for the numerical solution of lifting surface theory (DLM or VLM) must be at the 3-quarter-chord point of each element. Why? (ii) in the momentum theory about 3D wing, what should be the reference mass to exactly explain the lift and drag? In the present note, the two points are clarified with the help of some mathematical manipulations, using the models of an isolated horseshoe vortex and an elliptically load distributed bound vortex with a trailing vortex sheet., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA1630046004, レポート番号: JAXA-SP-16-008E

資料番号: DS1640286001