Formulation of Compressible and Not Expanding Fluid Dynamics and Study on Its Application to High-Speed Dense Dusty Flow

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H04585
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Aerospace engineering
• Research Institution: The University of Tokyo
• Principal Investigator: SUZUKI Kojiro 東京大学, 大学院新領域創成科学研究科, 教授 (10226508)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 航空宇宙工学 / 粉体流 / 数値流体力学 / 圧縮性流体力学 / 衝突現象 / バリスティックレンジ

Outline of Final Research Achievements

When an object moves at a high speed in a space filled with dense dust particles, the fine grains are formed by destructive collision and are aggregated into dusty clouds with higher density. To macroscopically describe such irreversible process, the “Compressible and Not Expanding” fluid model and the computational method to solve its flow were proposed. To observe granular flow around a high-speed object, the experimental technique to launch a projectile on a two-dimensional sheet of free-falling particles was developed. The characteristic features observed in the experiment, that is, the formation of the shock-wave-like structure in front of the body and the void in the wake region, were successfully simulated by the present model. Based on those techniques, various applications, for example, an umbrella-like membrane shield against the impact of dusty clouds, a numerical simulation of the planetary system formation from a disk of grains and so on, are expected.

Free Research Field

航空宇宙流体力学

Academic Significance and Societal Importance of the Research Achievements

衝突して粉砕、微粒子化して、さらにそれらが合体、凝集していく高濃度の高速粉体流れをマクロに表現するために圧縮するが膨張はしない流体という、通常の流体にはない性質を持つ新しいモデルを構築し、流体力学の適用可能性を広げたことが学術的意義である。小惑星探査機はやぶさ２に代表されるように宇宙探査に対する科学的興味は天体表面の観察に留まらず、その内部構造へと広がりつつある。一方、地上では、火山の噴火などにおいて高濃度ダスト流の現象が安全に直接関わってくる。それらを理解し、身を守るシールド開発などへとつなげていくことが大切である。本研究成果はそれらの要望に応えるための基礎となっている。