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Space–time correlation measurements of high-speed axisymmetric jets using optical deflectometry

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Abstract

An optical deflectometry system is used to provide unique space–time correlation measurements at two positions separated by varying axial distances within a high-speed jet shear layer. The measurements were made for both pure air and for helium/air mixture jets at Mach numbers M=0.9 and M=1.5. The jets issue from round nozzles and the sensing volumes at the two measurement positions consist of small light filaments along spanwise lines that are tangential to the annular jet shear layer. Applying this technique to obtain measurements detailing the level of correlation, spectral content, and convection velocity for jet flows in these flow regimes near the end of the potential core is particularly important in the understanding and prediction of jet noise. Measurements near the end of the potential core along the jet lip line exhibit distinct cross-correlation curves for the pure air jet cases. However, helium/air mixture jets display much lower levels of correlation and little evidence of large-scale structure in the measured spectra. It is believed that the thick visual density gradients dominated by smaller scales throughout the shear layer of the helium/air mixture jets effectively mask the large-scale structure, thus, reflecting a limitation of this optical deflectometer. Finally, a decrease in normalized convection velocity with helium addition is observed.

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Abbreviations

a :

Acoustic velocity

D :

Jet exit diameter

e :

Signal voltage

f :

Frequency

f c :

Characteristic frequency (=U j /D)

G 11 :

Autospectral density function for channel 1 (stationary probe)

G 22 :

Autospectral density function for channel 2 (moving probe)

G 12 :

Cross-spectral density function of channels 1 and 2

M :

Mach number

P, p:

Pressure

r :

Radial coordinate

R :

Correlation function

R 11 :

Autocorrelation function for channel 1 (stationary probe)

R 22 :

Autocorrelation function for channel 2 (moving probe)

R 12 :

Cross-correlation function of channels 1 and 2

Re :

Reynolds number

St :

Strouhal number

T :

Temperature

U :

Jet exit mean velocity

u :

Axial velocity component

v :

Transverse velocity component

x :

Axial coordinate

y :

Transverse coordinate

γ 212 :

Coherence function

ρ :

Density

ρ 12 :

Cross-correlation coefficient function

τ :

Time delay

Ψ :

Value of ordinate for deflectometry spectra

ψ 2 :

Mean square value

a:

Ambient property

c:

Convective quantity

j:

Jet quantity

o:

Stagnation quantity

rms:

Root-mean-square quantity

()*:

Simulated heated jet property using helium/air mixture

()′:

Fluctuating quantity

References

  • Alvi FS, Settles GS, Weinstein LM (1993) A sharp focusing schlieren optical deflectometer. AIAA paper 93-0629

  • Bradshaw P, Ferriss DH, Johnson RF (1963) Turbulence in the noise-producing region of a circular jet. J Fluid Mech 19:591–624

    Google Scholar 

  • Bridges J, Podboy GG (1999) Measurements of two-point velocity correlations in a round jet with application to jet noise. AIAA paper 99-1966

  • Bridges J, Wernet MP (2003) Measurements of the aeroacoustic sound source in hot jets. AIAA paper 2003-3130

  • Chu WT (1966) Turbulence measurements relevant to jet noise. University of Toronto, Institute for Aerospace Studies (UTIAS), report no. 119

  • Crow SC, Champagne FH (1971) Orderly structure in jet turbulence. J Fluid Mech 48:547–591

    Google Scholar 

  • Damkevala RJ, Grosche FR, Guest SH (1974) Direct measurement of sound sources in air jets using the crossed beam correlation technique. Noise mechanisms. AGARD-CP-131, pp 3.1–3.16

  • Davies POAL, Fisher MJ, Barratt MJ (1962) The characteristics of the turbulence in the mixing region of a round jet. J Fluid Mech 15:337–367

    Google Scholar 

  • Davis MR, (1971) Measurements in a subsonic turbulent jet using a quantitative schlieren technique. J Fluid Mech 46:631–656

    Google Scholar 

  • Doty MJ, McLaughlin DK (2003) Acoustic and mean flow measurements of high-speed helium–air mixture jets. Int J Aeroacoust 2:293–333

    Google Scholar 

  • Fisher MJ, Krause FR (1967) The crossed-beam correlation technique. J Fluid Mech 28:705–717

    Google Scholar 

  • Garg S, Settles GS (1998) Measurements of a supersonic turbulent boundary layer by focusing schlieren deflectometry. Exp Fluids 25:254–264

    Google Scholar 

  • Harper-Bourne M (1999) Jet near-field noise prediction. AIAA paper 99-27825

  • Harper-Bourne M, Fisher MJ (1974) The noise from shock waves in supersonic jets. Noise mechanisms. AGARD-CP-131, pp 11.1–11.13

  • Kinzie KW, McLaughlin DK (1999) Aeroacoustic properties of supersonic elliptic jets. J Fluid Mech 395:1–28

    Google Scholar 

  • Lau JC (1980) Laser velocimeter correlation measurements in subsonic and supersonic jets. J Sound Vib 70:85–101

    Google Scholar 

  • Lau JC (1981) Effects of exit Mach number and temperature on mean-flow and turbulence characteristics in round jets. J Fluid Mech 105:193–218

    Google Scholar 

  • Lighthill MJ (1952) On sound generated aerodynamically. I. General theory. P Roy Soc Lond A Mat 211:564–587

    Google Scholar 

  • Massier PF, Parthasarathy RF, Cuffel RF (1974) Experimental evaluation of fluctuating density and radiated jet noise from a high-temperature jet. Noise mechanisms. AGARD-CP-131, pp 2.1–2.13

  • McIntyre SS (1994) Optical experiments and instrument development for compressible turbulent mixing layers. PhD thesis, The Pennsylvania State University

  • McIntyre SS, Settles GS (1991) Optical experiments on axisymmetric compressible turbulent mixing layers. AIAA paper 91-0623

  • Morris PJ, Bhat TRS (1993) Supersonic elliptic jet noise. AIAA paper 93-4409

  • Oakley TR, Loth E, Adrian RJ (1996) Cinematic particle image velocimetry of high-Reynolds-number turbulent free shear layer. AIAA J 34(2):299–308

    Google Scholar 

  • Panda J, Seasholtz RG (2002) Measurement of correlation between flow density, velocity, and density*velocity2 with far field noise in high speed jets. AIAA paper 2002-2485

  • Seiner JM, Ponton MK, Jansen BJ, Lagen NT (1992) The effects of temperature on supersonic jet noise emission. German Society for Aeronautics and Astronautics (DGLR)/AIAA paper 92-02-046

  • Stromberg JL, McLaughlin DK, Troutt TR (1980) Flow field and acoustic properties of a Mach number 0.9 jet at a low Reynolds number. J Sound Vib 72(2):159–176

    Google Scholar 

  • Tesson V, Doty MJ, McLaughlin DK (2002) Experimental investigation of core noise and jet noise using a small gas turbine engine. AIAA paper 2002–2558

  • Wilson LN, Damkevala RJ (1970) Statistical properties of turbulent density fluctuations. J Fluid Mech 43:291–303

    Google Scholar 

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Acknowledgements

This work has been supported by NASA Langley Research Center through a Graduate Student Researcher’s Program Fellowship monitored by Mr. Tom Norum, Dr. Russ Thomas, and Dr. Kevin Kinzie. The authors thank Dr. P.J. Morris and Dr. G.S. Settles for their helpful discussions, as well as Mr. Vincent Tesson and Mr. Vincent Vielfaure for their contributions. Additional thanks go to Mr. Judson Rupert and Mr. Shawn Brechbill for providing facility support.

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Authors and Affiliations

  1. Rolls-Royce Corporation, P.O. Box 420, Speed Code T-10B, Indianapolis, IN, 46206, USA

    Michael J. Doty

  2. Department of Aerospace Engineering, The Pennsylvania State University, University Park, PA, 16802, USA

    Dennis K. McLaughlin

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  1. Michael J. Doty
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  2. Dennis K. McLaughlin
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Correspondence to Michael J. Doty.

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Doty, M.J., McLaughlin, D.K. Space–time correlation measurements of high-speed axisymmetric jets using optical deflectometry. Exp Fluids 38, 415–425 (2005). https://doi.org/10.1007/s00348-004-0920-1

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  • DOI: https://doi.org/10.1007/s00348-004-0920-1

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