Jet noise is one of the major sources of takeoff and landing noise at airports. The noise is also known to sometimes cause more complicated jet noise-airframe interference problems. Several prediction methods have been proposed to assess this issue in the past. However, the advantages and disadvantages of these methods have not been investigated sufficiently. In this study, three different approaches (i.e., an empirical method, a theoretical method, and an analytical method using the boundary element method) are utilized to predict the effects of a single jet with a horizontal tail. These results are compared with experimental data to clarify the difference. Whereas the results show that none of the three methods can predict noise effects perfectly, we extracted information that can be used as a guideline to choose an appropriate method in the future.

IKAROS, a solar sail spacecraft launched in 2010, demonstrated that thin-film solar cells can generate electricity. During this demonstration, it was found that the cells became curved, which destabilized the attitude of the spacecraft. Therefore, this study focused on a sputtering deposition technique that generates internal stress during the formation of thin films. The objective of this study was to control the curvature of a multilayer film by sputtering with a pattern. The effect of sputtering on the thin film was analyzed through experiments and simulations, and it was clarified that the cause of shape non-reproducibility is sputtering-induced stress.