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Dr Yu Liu

Lecturer in Aerospace Engineering

Qualifications: BSc, MSc, PhD

Email:
Phone: Work: 01483 68 2352
Room no: 12 AB 03

Further information

Biography

Yu Liu graduated from Beijing University of Aeronautics and Astronautics (BUAA) with a BSc and an MSc in Aerospace Engineering - Jet Propulsion. He received his PhD in Aeroacoustics (2008) under the supervision of Prof. Dame Ann Dowling from the University of Cambridge, funded by the Overseas Research Students Awards Scheme and the Gates Cambridge Scholarships.

His PhD study was on surface roughness generated boundary layer noise, as part of the Silent Aircraft Initiative which was a collaborative project sponsored by the Cambridge-MIT Institute. He then conducted postdoctoral research at University of Illinois at Urbana-Champaign (UIUC) on jet noise and rocket acoustics, and at University of Cambridge on combustion noise as part of the TSB SYMPHONY project.

In October 2012, Yu Liu joined the University of Surrey as a Lecturer in Aerospace Engineering. 

Yu Liu is interested in taking PhD students (self-funded and externally funded). Please see 'More...' for current PhD opportunities.
 

Research Interests

  • Aeroacoustics, aircraft noise prediction and control
  • Fluid mechanics, flow induced noise and vibration
  • Thermoacoustics, combustion noise, rocket acoustics
  • Phased microphone array and acoustic beamforming algorithm
  • Gas turbine technologies, etc.

Research Collaborations

  • Rolls-Royce plc
  • University of Cambridge

Publications

Journal articles

  • Liu Y, Dowling AP, Swaminathan N, Morvant R, Macquisten MA, Caracciolo LF. (2013) 'Prediction of Combustion Noise for an Aeroengine Combustor'. AIAA Journal of Propulsion and Power,
    [ Status: Submitted ]
  • Liu Y. (2012) 'Assessment of Surface Roughness Noise for a 'Silent' Aircraft'. The Aeronautical Journal,
  • Liu Y, Dowling AP, Swaminathan N, Dunstan TD. (2012) 'Spatial Correlation of Heat Release Rate and Sound Emission from Turbulent Premixed Flames'. Combustion and Flame, 159 (7), pp. 2430-2440.
    doi: 10.1016/j.combustflame.2012.03.003
  • Liu Y, Quayle AR, Dowling AP, Sijtsma P. (2008) 'Beamforming Correction for Dipole Measurement Using Two-Dimensional Microphone Arrays'. Journal of the Acoustical Society of America, 124 (1), pp. 182-191.
    doi: 10.1121/1.2931950
    Full text is available at: http://epubs.surrey.ac.uk/735297/

    Abstract

    In this paper, a beamforming correction for identifying dipole sources by means of phased microphone array measurements is presented and implemented numerically and experimentally. Conventional beamforming techniques, which are developed for monopole sources, can lead to significant errors when applied to reconstruct dipole sources. A previous correction technique to microphone signals is extended to account for both source location and source power for two-dimensional microphone arrays. The new dipole-beamforming algorithm is developed by modifying the basic source definition used for beamforming. This technique improves the previous signal correction method and yields a beamformer applicable to sources which are suspected to be dipole in nature. Numerical simulations are performed, which validate the capability of this beamformer to recover ideal dipole sources. The beamforming correction is applied to the identification of realistic aeolian-tone dipoles and shows an improvement of array performance on estimating dipole source powers.

  • Liu Y, Dowling AP, Shin HC. (2008) 'Measurement and Simulation of Surface Roughness Noise Using Phased Microphone Arrays'. Journal of Sound and Vibration, 314 (1-2), pp. 95-112.
    doi: 10.1016/j.jsv.2007.12.041
  • Liu Y, Dowling AP. (2007) 'Assessment of the Contribution of Surface Roughness to Airframe Noise'. AIAA Journal, 45 (4), pp. 855-869.
    doi: 10.2514/1.25217
    Full text is available at: http://epubs.surrey.ac.uk/735295/

    Abstract

    The generation of sound by turbulent boundary-layer flow at low Mach number over a rough wall is investigated by applying a theoretical model that describes the scattering of the turbulence near field into sound by roughness elements. Attention is focused on the numerical method to approximately quantify the absolute level of far-field radiated roughness noise. Models for the source statistics are obtained by scaling smooth-wall data by the increased skin friction velocity and boundary-layer thickness for a rough surface. Numerical integration is performed to determine the roughness noise, and it reproduces the spectral characteristics of the available empirical formula and experimental data. Experiments are conducted to measure the radiated sound from two rough plates in an open jet. The measured noise spectra of the rough plates are above that of a smooth plate in 1–2.5 kHz frequency and exhibit reasonable agreement with the predicted level. Estimates of the roughness noise for a Boeing 757 sized aircraft wing with idealized levels of surface roughness show that in the high-frequency region the sound radiated from surface roughness may exceed that from the trailing edge, and higher overall sound pressure levels are observed for the roughness noise. The trailing edge noise is also enhanced by surface roughness somewhat. A parametric study indicates that roughness height and roughness density significantly affect the roughness noise with roughness height having the dominant effect. The roughness noise directivity varies with different levels of surface roughness.

  • Du L, Liu Y, Sun X. (2005) 'Research on the Sound Propagation and Radiation in a Duct with a Non-Locally Reacting Liner'. Journal of Engineering Thermophysics, 26 (5), pp. 751-754.

Conference papers

  • Liu Y, Dowling AP, Dunstan TD, Swaminathan N. (2012) 'Modelling of Combustion Noise Spectrum from Turbulent Premixed Flames'. Nantes, France: ACOUSTICS 2012, Paper No. 000734
  • Liu Y, Dowling AP, Morvant R, Macquisten MA, Caracciolo LF. (2011) 'Prediction of Noise Source for an Aeroengine Combustor'. Portland, US: The 17th AIAA/CEAS Aeroacoustics Conference, AIAA Paper 2011-2913
  • Liu Y, Dowling AP, Quayle AR. (2008) 'Numerical Simulation of Beamforming Correction for Dipole Source Identification'. Berlin, Germany: The 2nd Berlin Beamforming Conference (BeBeC), Paper No. 22
  • Quayle AR, Dowling AP, Babinsky H, Graham WR, Liu Y. (2008) 'Mechanisms for Model Scale Landing Gear Noise Generation'. Reno, US: The 46th AIAA Aerospace Sciences Meeting and Exhibit, AIAA Paper 2008-0016
  • Liu Y, Dowling AP, Hileman JI, Quayle AR. (2008) 'Surface Roughness Noise Prediction for Silent Aircraft eXperimental Design SAX-40'. Reno, US: The 46th AIAA Aerospace Sciences Meeting and Exhibit, AIAA Paper 2008-0045
  • Liu Y, Dowling AP, Shin HC. (2007) 'Experimental Study of Surface Roughness Noise'. Rome, Italy: The 13th AIAA/CEAS Aeroacoustics Conference, AIAA Paper 2007-3449
  • Quayle AR, Dowling AP, Babinsky H, Graham WR, Liu Y. (2007) 'Phased Array Measurements from Landing Gear Models'. Rome, Italy: The 13th AIAA/CEAS Aeroacoustics Conference, AIAA Paper 2007-3463
  • Liu Y, Dowling AP, Shin HC. (2006) 'Application of Phased Arrays in the Study of Surface Roughness Noise'. Berlin, Germany: The 1st Berlin Beamforming Conference (BeBeC), Paper No. 16
  • Liu Y, Dowling AP. (2006) 'Effects of Surface Roughness on Airframe Noise'. Cambridge, US: The 12th AIAA/CEAS Aeroacoustics Conference, AIAA Paper 2006-2510
  • Sun X, Liu Y, Du L. (2005) 'A Numerical Technique for Computation of Sound Radiation of Aeroengine Duct with Acoustic Liners'. Japan Science and Technology Agency Japan: The 45th Conference on Aerospace Propulsion, Paper No. 05A0321590 45
  • Liu Y, Du L, Sun X. (2004) 'Propagation in Circular Ducts with Non-Locally Reacting Liners'. Xi'an, China: The 12th Annual Conference of the Chinese Institute of Engineering Thermophysics, Paper No. 04-2063

Reports

  • Liu Y, Dowling AP, Hynes TP. (2012) Combustion Noise Modelling. in (ed.) UGTP (University Gas Turbine Partnership) Annual Report University of Cambridge
  • Liu Y. (2011) Validated Combustion Noise Code and Documentation. in (ed.) SYMPHONY WP1 T2 Deliverable D1.2.3 Rolls-Royce plc
  • Liu Y. (2011) Comparison of Predicted and Engine Measured Combustion Noise. in (ed.) SYMPHONY WP1 T2 Deliverable D1.2.2 Rolls-Royce plc
  • Liu Y. (2010) Combustion Sound Pressure Transfer Function. in (ed.) SYMPHONY WP1 T2 Deliverable D1.2.1 Rolls-Royce plc
  • Liu Y. (2010) Modelling Approach and Choice of Low Order Model for Combustion Noise Source. in (ed.) SYMPHONY WP1 T2 Deliverable D1.2.4 Rolls-Royce plc

Theses and dissertations

  • Liu Y. (2008) Surface Roughness Generated Boundary Layer Noise. PhD Thesis (University of Cambridge, UK)
  • Liu Y. (2004) Effects of Non-Locally Reacting Liners on Sound Propagation and Radiation in Flow Ducts. MSc Thesis (Beijing Univ. of Aero. & Astro., China)

Teaching

Supervision

  • ENG M001   Multi-Disciplinary Design Project (MDDP, Master Level)
  • ENG 3162    Group Design Project (Aircraft Design, UG Level 3)
  • ENG 3101    BEng Final Year Research Project

Affiliations

Referee Services

PhD Opportunities

  • Entropy noise control with acoustic perforated liner
  • Prediction and control of wind turbine noise
  • Design of low noise landing gear
  • Trailing edge noise reduction through boundary layer control