Wall surface design for shock wave confinement region control

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K04182
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19010:Fluid engineering-related
• Research Institution: Nara National College of Technology
• Principal Investigator: Fukuoka Hiroshi 奈良工業高等専門学校, 機械工学科, 准教授 (40582648)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 圧縮性流体 / 超音速噴流 / 衝撃波 / 反射衝撃波 / 収束現象 / 閉じ込め / 可視化 / ３D数値解析

Outline of Final Research Achievements

In this study, we obtained design guidelines for the wall surface shape that controls the multiple confinement phenomenon of shock waves, a crucial issue in industry, new energy, and material development. We experimentally demonstrated the design guidelines. In order to clarify the physical conditions necessary for confinement, measurement experiments using a concave-shaped reflector, which is thought to be able to change the physical conditions of the shock wave, revealed experimentally the positional relationship between the convergence position of the shock wave and the jet stream. This indicates that shock waves of various strengths can impinge on the jet, which will be important in the design of future geometries. Furthermore, we found the possibility that the reflection of the shock wave by the jet can be qualitatively organized in terms of acoustic impedance.

Free Research Field

流体力学

Academic Significance and Societal Importance of the Research Achievements

これまで衝撃波が壁面で反射する現象についての基礎的研究は行われてきたが，噴流との反射に関してはほとんど存在なかった．本研究では，噴流と様々な衝撃波を衝突させることで，反射の過程を明らかにした．その結果，噴流および衝撃波が衝突する直前の物理的状態が，衝撃波の反射に大きく影響し，衝撃波および噴流の制御が閉じ込めの指針になることを示した．