豊橋技術科学大学

Search

Search

Yokoyama, Hiroshi

Japanese

Affiliation Department of Mechanical Engineering
Title Professor
Fields of Research Fluid engineering, Aeroacoustics, Computational fluid dynamics, Thermoacoustics
Degree Doctor of Philosophy in Engineering (The University of Tokyo)
Academic Societies Japan Society of Mechanical Engineers, Society of Automotive Engineers of Japan, The Visualization Society of Japan, The Japan Society of Fluid Mechanics, The American Institute of Aeronautics and Astronautics
E-mail h-yokoyama@me
Please append ".tut.ac.jp" to the end of the address above.
Laboratory website URL https://ec.me.tut.ac.jp/
Researcher information URL（researchmap） Researcher information

Research

Abstract

I am interested in complex phenomena related with fluid-dynamics, aeroacoustics, thermodynamics, and EletroHydroDynamics. Especially, my objective is to establish design guide for high efficiency and reduced noise for automobiles, high-speed train and fluid-related machinery. Acoustic radiation around musical instruments is also my topic. Simulations using high-performance computers and wind tunnel experiments are performed. I completed my Ph.D (2010) for research of cavity tone after undergraduate studies at The University of Tokyo. I studied as a visiting academic in University of Southampton in U.K (2015-2016). I have been working in the department of mechanical engineering at Toyohashi University of Technology and a cooperative research fellow at The University of Tokyo since 2010.

Main themes

  1. Research for conservation of energy in fluid machinery or thermoacoustic device utilizing acoustic power and wasted heat
  2. Control of Aerodynamic noise generated from high-speed transports and fluid equipments
  3. Coupled problems such as acoustic radiation from musical instruments

Key words

Energy conservation, Aeroacoustics, Noise, Fluid machinery, Turbulence, Computational fluid dynamics, Cavity, Fan, Plasma actuators, Musical instruments, High-speed vehicles

Main publications

  1. H. Yokoyama, I. Tanimoto, A. Iida,"Experimental Tests and Aeroacoustic Simulations of the Control of Cavity Tone by Plasma Actuators", Appl. Sci. 2017, 7(8), 790, pp.1-15; doi:10.3390/app7080790.(The figures of this paper was on cover page of this issue)
  2. T. Miyamoto, H. Yokoyama, A. Iida,"Suppression of Aerodynamic Tonal Noise from an Automobile Bonnet Using a Plasma Actuator", SAE Int. J. Passeng. Cars - Mech. Syst. 10(3):2017, pp.22-30. doi:10.4271/2017-01-1825.
  3. H. Yokoyama, Y. Hirose, A. Iida, "Effective mixing and aeration in a bioreactor with Taylor vortex flow", Mechanical Engineering Letters, 2, 16-00412, pp.1-9, 2016
  4. H.Yokoyama H, A. Miki, H. Onitsuka, A. Iida, "Direct numerical simulation of fluid-acoustic interactions in a recorder with tone holes", Journal of the Acoustical Society of America, 138(2), pp.858-873,2015
  5. H. Yokoyama, K. Kitamiya, A. Iida, "Flows around a cascade of flat plates with acoustic resonance", Physics of Fluids, 25(10), 106104-1-106104-22, 2013
  6. H. Yokoyama, C. Kato, "Fluid-acoustic interactions in self-sustained oscillations in turbulent cavity flows. I. Fluid-dynamic oscillations", Physics of Fluids, 21(10), 105103-1-105103-13, 2009
  7. H. Yokoyama, Y. Tsukamoto, C. Kato, A. Iida, "Self-sustained oscillations with acoustic feedback in flows over a backward-facing step with a small upstream step", Physics of Fluids, 19(10), 106104-1-106104-8, 2007

Academic networks: researchmap Google scholar ResearchGate ORCiD Scopus

Theme1：Clarification of radiation mechanism and control for aerodynamic sound

Overview
Vortices around an axial-flow fan

Aerodynamic noise increases in proportional to the high power of velocity. So, the noise is a sever problem for high-speed transport vehicles or flow-related machinery. For example, intense tonal sound radiates from cavity flow and flow around a cascade of flat plates, where the feedback loop due to fluid-acoustic interactions occurs. To clarify the mechanism of acoustic radiation and establish the methodologies for noise reduction, we perform wind tunnel experiments and aeroacoustic direct numerical simulation (AADNS). Also, to establish the prediction method of aerodynamic noise, decoupled simulations consisting of acoustic and flow simulations are focused on.

○Cavity tone
○Control of aerodynamic noise by plasma actuators
○Aerodynamic noise from flows around a cascade of flat plates with acoustic resonance
○Tonal sound from automobiles parts such as bonnet, door mirror and sunroof
○Decoupled simulations based on Lighthill analogy

Selected publications and works
  1. H. Yokoyama, K. Otsuka, K. Otake, M. Nishikawara, H. Yanada, Control of Cavity Flow with Acoustic Radiation by an Intermittently Driven Plasma Actuator, Physics of Fluids, 32(10),106104, pp.1-20, 2020
  2. H. Yokoyama, K. Minowa, K. Orito, M. Nishikawara, H. Yanada, Compressible Simulation of Flow and Sound around a Small Axial-Flow Fan with Flow through Casing Slits, Journal of Fluids Engineering, Transactions of the ASME, 142(10), 101215, pp.1-10, 2020
  3. H. Yokoyama, K. Kitamiya, and A. Iida, Flows around a cascade of flat plates with acoustics resonance, Physics of Fluids, 25(10), 106104, 2013.
  4. H. Yokoyama and C. Kato, Fluid-acoustic interactions in self-sustained oscillations in turbulent cavity flows. I. Fluid-dynamic oscillations, Physics of Fluids 21, 105103 (2009).
  5. H. Yokoyama, Y. Tsukamoto, C. Kato and A. Iida, Self-Sustained Oscillations with Acoustic Feedback in Flow Over a Backward-Facing Step with a Small Upstream Step, Physics of Fluids19, 106104 (2007).

Keywords

Aeroacoustics, Direct simulation, Fluid-acoustic interactions, Wind tunnel experiments

Theme2：Simulations of coupled dynamics related with aeroacoustics

Overview
Visualized sound from musical instrument

　The computational methodology for prediction of coupled dynamic phenomena related with fluid and acoustics has been developed.
In air-reed instruments such as a recorder, the flow velocity fluctuates by the blowing of performer. These fluctuations generate sound (pressure and density fluctuations). The simulations can include the body force electrically induced in the flow such as plasma actuators and thermal conduction in a object such as thermoacoustic heat pump.

Selected publications and works
  1. H. Yokoyama, M. Kobayashi, A. Iida, Analysis of Flow and Acoustic Radiation in Reed Instruments by Compressible Flow Simulation, Acoustical Science and Technology, Vol.41, No.5, E1926, pp.739-750, 2020
  2. Y. Tanaka Y, H. Yokoyama, A. Iida, "Forced-oscillation control of sound radiated from the flow around a cascade of flat plates", Journal of Sound and Vibration, 431, pp.248-264, 2018
  3. H. Yokoyama, A. Miki, H. Onitsuka, A. Iida, "Direct numerical simulation of fluid-acoustic interactions in a recorder with tone holes", Journal of the Acoustical Society of America, 138(2) 858-873, 2015

Keywords

Musical instrument, aeroacoustic direct simulation, Air-reed instrument, Reed instrument, Volume penalization, Immersed boundary method

Theme3：Utilization of acoustic energy for Low Environmental Load

Overview
Evaluation of promotion effects of CO2 adsorption effects with acoustic excitation

For utilization of acoustic energy and wasted heat, thermoacoustic phenomena of conversion of sound and heat energies and adsorption promotion effects of sound are focused on.

Selected publications and works
  1. H. Yokoyama, K. Yoza, M. Nishikawara, H. Yanada, Simulation of acoustic oscillatory flows around a curvature controlled by a plasma actuator, Applied Acoustics, 205, 109274, 2023
  2. H. Yokoyama, Y. Omori, M. Kume, M. Nishikawara, H. Yanada, Simulation of thermoacoustic heat pump effects driven by acoustic radiation in a cavity flow, International Journal of Heat and Mass Transfer, 185, 122424, pp.1-17, 2022
  3. H. Yokoyama, Y. Hirose, A. Iida，Effective mixing and aeration in a bioreactor with Taylor vortex flow, Mechanical Engineering Letters, 2(16-00412) 1-9, 2016

Keywords

Acoustic energy, Thermoacoutic phenomena, CO2 adsorption, Bioreactor, Wasted heat

Title of class

○Fluid Mechanics (B11620110)
○Creative Experiment for Mechanical Engineering (B11610103)
○Fluid Energy Conversion (B11624090)
○Computational Fluid Dynamics (M21624170)
〇Advanced Fluid and Energy Engineering (M41630540)
○Advanced Environmental Engineering (D51030080)

Others (Awards, Committees, Board members)

Awards

  1. Mar. 2023, The NAGAI Foundation for Science ＆ Technology, Academic Award
  2. Apr. 2019, The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology, The Young Scientists
  3. May 2018, The Asahara Science Award, Society of Automotive Engineers of Japan
  4. Apr. 2012, JSME Medal for Outstanding Paper, The Japan Society of Mechanical Engineers
  5. Apr. 2011, JSME Young Engineers Award, The Japan Society of Mechanical Engineers
  6. Mar. 2007, Society of Automotive Engineers of Japan, Prediction of tonal sound from side mirror, Best paper award

Press

  1. New Scientist, "See how sound radiates around a recorder", February 2015
  2. EurekAlert!, "Supercomputer simulations explore how an air-reed instrument generates air flow and sound", February 2015
  3. iSGTW (international science grid this week), "Simulating sound with supercomputers could lead to development of easy-to-play musical instruments", March 2015"

Committees, Board members

  1. 2023- The Japan Society of Fluid Mechanics, Delegate
  2. 2022- JSME Computational Mechanics Division, CMD2023, Secretary
  3. 2022- Society of Automotive Engineers of Japan, Chubu, Advisor
  4. 2019-2021 The Visualization Society of Japan, Delegate
  5. 2018-2021 The Japan Society of Fluid Mechanics, Chubu, Acting committee(2021, Secretary)
  6. 2018-2019 JSME, Tokai, Gakuseikai, Advisor, 2018-
  7. 2017-2018 Experimental and Numerical Flow and Heat Transfer Scientific Committee member
  8. 2017 JSME Power&System Energy Division Symposium, Acting committee
  9. Apr. 2014 - Mar. 2017 JSME Fluids Engineering Division Committee on Public Information
  10. Apr. 2012 - Mar. 2015 JSME Fluids Engineering Division Acting committee
  11. Apr. 2010 - Jul. 2014 The Visualization Society of Japan Acting Committee of Symposium on Visualization

Research Grants and Projects

  1. HPCI System Research Project, Project ID: hp230012 (main)
  2. MEXT: KAKENHI, KIBAN(C), Project Year: 2021 - 2024 (main)
  3. MEXT: KAKENHI, KIBAN(C), Project Year: 2017 - 2020 (main)
  4. MEXT: KAKENHI, WAKATE(B), Project Year: 2014 - 2016 (main)
  5. MEXT: KAKENHI, KIBAN(B), Project Year: 2013 - 2015 (shared)
  6. MEXT: KAKENHI, WAKATE(B), Project Year: 2012 - 2013 (main)

to Pagetop