Midair Flow Control with High Spatiotemporal Resolution based on Ultrasound-Driven Streaming

2021 Fiscal Year Final Research Report

• Project/Area Number: 18H01458
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 21040:Control and system engineering-related
• Research Institution: The University of Tokyo
• Principal Investigator: Hasegawa Keisuke 東京大学, 大学院情報理工学系研究科, 講師 (20733108)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 非線形音響現象 / 収束超音波 / 音響流 / 気流制御

Outline of Final Research Achievements

The main results of this research are summarized into the three following topics. (1) A construction method of acoustic intensity field that corresponds to acoustic streaming field to generate is established by means of continuous optimization of amplitude distribution with a proper regularization. (2) An arc-shaped intense ultrasound beam is generated by creating series of congregative ultrasound foci that forms the beam. It is verified that the acceleration of air is done in direction of the beam tangent at each line segment of the beam. (3) Binary M-sequence pattern of ultrasound amplitude is generated in the workspace to enable a single monoaural microphone to estimate its self-position. In this framework, the amplitude pattern is spatially scanned so that the microphone position can be retrieved using amplitude signal received by the microphone as a position-dependent positional clue.

Free Research Field

超音波工学

Academic Significance and Societal Importance of the Research Achievements

従来のファンやジェットで実現するものよりも時空間的な自由度の高い流れを設計し、音響流を用いることで初めて生成可能な性質の気流の実現および新たな応用提案をおこなうことにより、ヒトの生活空間における空気制御の有力な手法としての音響流の利用をこれまでよりも説得力のある形で示すことができた。同時に、「目的に応じた時空間分布を持つ超音波音場（構造化超音波音場）」の新しい用途としてモノラルマイクロホンの非同期自己定位などの可能性を示し、生活空間における超音波の利用についても併せて新しい応用シナリオを提示できた。