Akira Oyama

大気球シンポジウム 平成26年度（2014年11月6-7日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)）, 相模原市, 神奈川県著者人数: 18名資料番号: SA6000021006レポート番号: isas14-sbs-006

DESTINY is injected to long elliptical orbit by Epsilon rocket launcher. If the apogee altitude of the injected orbit is high enough, it is achieved to ease the requirements for design and operation of the spacecraft. This paper investigates the ability of trajectory injection by means of 4-stage Epsilon rocket using the method of multi objective optimization under several flight constraints.

Large-scale multiobjective design exploration using K computer is presented. This presentation includes aeroacoustic design optimization problem of a rocket launch site and aerodynamic design optimization problem of a plasma actuator applied to a wing model. Non-dominated solutions visualization tool named iSPM is also introduced.

A novel algorithm for many-objective optimization based on continuous Ant Colony Optimization (AGO) is proposed.

In this study, multiobjective design exploration for a rocket launch site is conducted using evolutionary computation with large eddy simulation to understand the acoustic characteristics associated with various launch sites. The launch site is described by curved surface. The flat plate inclined with 45 degree is considered as the reference configuration. The objective functions of multiobjective aero-acoustic design optimization are, 1) minimization of averaged sound pressure level near the payload fairing, 2) minimization of maximum pressure on the curved surface of the rocket launch site, and 3) minimization of the change of the curved surface from the reference configuration. Three-dimensional compressible Navier-Stokes equations are solved with the modified weighted compact nonlinear scheme. The total number of evaluation is 2500, and the evaluation of one generation necessitates the use of 6500 nodes using "K" supercomputer. As the results of the flow field analysis of some characteristic non-dominated solutions show the characteristics of acoustic wave and the location of the maximum gradient of the curved surface.

To understand the effects of working parameters of the DBD plasma actuator, investigation with a Multi-Objective Design Exploration(MODE) framework is performed. Experiments with a NACA 0015 airfoil fixed to the stall angle of 12 degrees are conducted at Reynolds number of 63,000. The optimization objectives are to maximize the lift coefficient C_l and minimize the power consumption P. The design variables consist of input power parameters. Despite the small population size, an approximate Pareto-optimal front is found. In the objective function space, a region where there exists a linear relationship between C_l and P is found. After a threshold value, the value of C_l seems to saturate. This paper concentrates on this linear region of the objective function space. We use numerical simulation results with similar parameters to several Pareto-optimal experiment cases to compliment our discussion.