大山 聖

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 and find design information such as trade-off relation among design objectives. 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. The total number of evaluation in multiobjective evolutionary computation is 2500. The analysis of non-dominated solutions clearly show that there are various trade-off relations and correlations among the objective functions.

This paper presents applications of multiobjective design optimization (MDO) and multiobjective design exploration (MODE) in space engineering. These applications include hybrid rocket conceptual design, spacecraft trajectory design, rocket engine design and aerodynamic reusable sounding rocket design. This paper also discusses limitations of current MDO and MODE and presents real-world design optimization test problems and a new approach to extract useful design information from non-dominated solutions of optimization problems.

The dielectric barrier electric discharge plasma actuator is expected as a new technology which can make the design of an aerofoil etc. unnecessary. The boundary layer control might be able to be performed by induced velocity in the boundary layer as an effect of the dielectric substance barrier electrical discharge plasma actuator. Moreover, it also turns out that the control effectiveness increases by repeating ON and OFF of the applied voltage, which is called burst. In this study, separation control on an airfoil by a plasma actuator was performed, and its control effectiveness was evaluated. This paper showed the effective mechanism of burst control by PIV.

The dielectric barrier electric discharge plasma actuator is expected as a new technology which can make the design of an aerofoil etc. unnecessary. The boundary layer control might be able to be performed by induced velocity in the boundary layer as an effect of the dielectric substance barrier electrical discharge plasma actuator. Moreover, it also turns out that the control effectiveness increases by repeating ON and OFF of the applied voltage, which is called burst. But, the control mechanism is unknown. In this study, separation control on an airfoil by a plasma actuator was performed, and its control effectiveness was evaluated. The result showed a possibility to change the control effectiveness with the burst frequency mainly.