豊橋技術科学大学

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Yokoyama, Hiroshi

Japanese

Affiliation Department of Mechanical Engineering
Title Associate 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 http://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 for aerodynamic sound

Overview
Voritices and pressure field in cavity flows

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. Kitamiya, H. Yamamoto, and A. Iida, "Effects of distance between plates on flows around a cascade of flat plates with acoustic resonance", AIAA-2014-3197, Atlanta, 20th AIAA/CEAS Aeroacoustics Conference, 2014
  2. H. Yokoyama, K. Kitamiya, and A. Iida, "Flows around a cascade of flat plates with acoustics resonance", Physics of Fluids, 25(10), 106104, 2013.
  3. H. Yokoyama and A. Iida, "Acoustic Radiation from Flows around a Cascade of Flat Plates", Korea-Japan CFD workshop 2012, Busan, Korea, 2012, 11.
  4. H. Yokoyama and C. Kato, "Fluid-Acoustic Interactions in Acoustic Radiation in Turbulent Cavity Flows (Fluid-Dynamic Oscillations)", Journal of Environment and Engineering, 6 (1), (2011).
  5. 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).
  6. 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：Development of computational methods of coupled problems of fluid, acoustic, oscillations

Overview
Visualized sound from musical instrument

　The computational methodology for prediction of phenomena related with coupling of fluid, acoustics and vibration 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). It had been known that a small change of the shape or material of instruments critically affects ease of playing or how a performer feels during performance. By the predicted results, we understand the way the sound is radiating from flows in the recorder.
Also, to increase lift of micro air vehicle and control aerodynamic noise, forced plate oscillation with constant frequency are applied for flow around the plate(s).

Selected publications and works
  1. Saya Sato, Hiroshi Yokoyama, Akiyoshi Iida, "Control of Flow around an Oscillating Plate for Lift Enhancement by Plasma Actuators", Applied Sciences, 9(4, applsci-428109) 776-1-776-19, 2019.
  2. Tanaka Y, Yokoyama H, Iida A., "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. M. Kobayashi, H. Yokoyama, A. iida, "Direct numerical simulation of flow and acoustic fields around woodwind instruments with reed oscillations", Inter-Noise 2017, Hong Kong, China.
  4. H. Yokoyama, M. Akira, R. Hamasuna, H. Onitsuka, A. Iida, “Direct aeroacoustic simulations and measurements of flow and acoustic fields around a recorder with tone holes”, The fifth joint ASA/ASJ meeting, 2016. [invited]
  5. H. Yokoyama, "Direct aeroacoustic simulation related with mode change in a recorder", Proceedings of ECCOMAS, 2016
  6. 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
  7. H. Yokoyama, M. Kobayashi, H. Onitsuka, A. Miki, A. iida, "Direct numerical simulation of flow and acoustic fields around an air-reed instrument with tone holes",inter-noise 2014, Melbourne, Australia, (November 17,2014).

Keywords

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

Theme3：Fluids Engineering for Low Environmental Load

Overview
Double-cylinder mixer for bioreactor

For conservation of energy, thermoacoustic device utilizing wasted heat and acoustic power, mixing device of bio-reactor, fan are developed. The thermoacoustic heat pump phenomena utilizing cavity tone due to self-sustained oscillations are clarified. Double-cylinder mixer for bio-reactor for the culture of algae is developed. The relationship between behavior of CO2 bubbles and culture of algae is focused on. We perform visualization of flow and simulation along with culture experiments. Regarding fan, objective is to establish both noise reduction and high performance. Moreover, to develop high-performance fluid-related machinery, flow control with various methods such as plasma actuators is developed.

Selected publications and works
    Katsutake Minowa, Hiroshi Yokoyama, Kohei Oriot, Akiyoshi Iida, "DIRECT AEROACOUSTIC SIMULATION OF FLOW AND NOISE AROUND AN AXIAL-FLOW FAN REGARDING EFFECTS OF SLITS IN A CASING", Proceedings of 26th International Congress on Sound and Vibration, 1-8, 2019.
  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). Link (open access)
  2. H. Yokoyama, R. Adachi, T. Minato, A. Iida, "Experimental and Numerical Investigations on Control Methods of Cavity Tone by Blowing Jet in an Upstream Boundary Layer", SAE Int. J. Passeng. Cars - Mech. Syst. 10(3):2017, pp.13-21. doi:10.4271/2017-01-1786.
  3. 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.
  4. 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
  5. S. Ullah, H. Yokoyama, A. Iida, Design and Fabrication of Two Stage Thermoacoustic Engine to Reduce the Onset Temperature，Proceedings of ECTE2016, 2016
  6. H. Yokoyama, R. Adachi, T. Minato, H. Odawara, H. Morishima and A. Iida, "Control of Cavity Tone by Spanwise Aligned Jets in Upstream Boundary Layer", European Drag Reduction and Flow Control Meeting 2015, (March, 2015)

Keywords

Bioreactor, Mixer, Double cylinder, Bubble flow, Thermoacoustic instruments, Fan, Control of flow

Title of class

○Fluid Mechanics (B11620110)
○Creative Experiment for Mechanical Engineering (B11610103)
○Computational Fluid Dynamics (M21624170)
○Advanced Environmental Enginnering (D51030080)

Others (Awards, Committees, Board members)

Awards

  1. Apr. 2019, The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology, The Young Scientists
  2. May 2018, The Asahara Science Award, Society of Automotive Engineers of Japan
  3. Apr. 2012, JSME Medal for Outstanding Paper, The Japan Society of Mechanical Engineers
  4. Apr. 2011, JSME Young Engineers Award, The Japan Society of Mechanical Engineers
  5. 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"
  4. The Visualization Society of Japan, "Today's Flash", July 2010"

Committees, Board members

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

Research Grants and Projects

  1. MEXT: KAKENHI, KIBAN(C), Project Year: 2017 - 2020 (main)
  2. MEXT: KAKENHI, WAKATE(B), Project Year: 2014 - 2016 (main)
  3. MEXT: KAKENHI, KIBAN(B), Project Year: 2013 - 2015 (shared)
  4. MEXT: KAKENHI, WAKATE(B), Project Year: 2012 - 2013 (main)

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