Abstract
Turbulent wall pressure fluctuation measurements were made in water on a towed model of length 129.8 (m) and diameter 3.8 (cm) for steady speeds from 6.2 (m/s) to 15.5 (m/s). The drag on the model was measured with a strut mounted load cell which provided estimates of the momentum thickness and friction velocity. Momentum thickness Reynolds numbers Re θ varied from 4.8 × 105 to 1.1 × 106. The ratio of momentum thickness to viscous length scale is significantly greater than for flat plate cases at comparable Re θ. The effectiveness of inner and outer velocity and length scales for collapsing the pressure spectra are discussed. The wavenumber–frequency spectra show a convective ridge at higher frequencies similar to flat plate boundary layers. At low frequencies, energy broad in wavenumber extends outside the convective ridge and acoustic cone, with no characteristic wave speed. Wall pressure cross-spectral levels scaled with similarity variables are shown to increase with increasing tow speed, and to follow decay constants consistent with flat plate cases. The convection velocities also display features similar to flat plate cases.
Similar content being viewed by others
Abbreviations
- d = 2a :
-
model diameter (mm)
- d s :
-
pressure sensor diameter (mm)
- D :
-
drag force (N)
- f :
-
cyclic frequency (Hz)
- k :
-
streamwise wavenumber (r/m)
- k 2 :
-
spanwise wavenumber (r/m)
- k c = ω/U c :
-
convective wavenumber (r/m)
- p :
-
fluctuating wall pressure (μPa)
- r :
-
radians
- Re θ = U oθ/ν:
-
momentum thickness Reynolds number
- s + = ν/u τ :
-
viscous length scale (mm)
- u τ = (τ/ρ)1/2 :
-
friction velocity (m/s)
- U c :
-
wall pressure convection velocity (m/s)
- U o :
-
carriage tow speed (m/s)
- δ:
-
turbulent boundary layer thickness (cm)
- ϕ = ωξ/U c :
-
cross-spectra phase (r)
- Φ(f) = Φ(ω)(2π):
-
autospectra (μPa2/Hz)
- Φ(ξ, f) = Φ(ξ, ω)(2π):
-
cross-spectra (μPa2/Hz)
- Φ(k, f) = Φ(k, ω)(2π):
-
wavenumber–frequency spectra (μPa2/(Hz (r/m)))
- γ(ωξ/U c):
-
coherence function (normalized)
- ν:
-
kinematic viscosity (m2/s)
- ρ:
-
fluid density (kg/m3)
- θ:
-
turbulent boundary layer momentum thickness (cm)
- τ:
-
mean wall shear stress (N/m2)
- ω:
-
radian frequency (r/s)
- ξ:
-
sensor streamwise separation (mm)
References
Abraham BM, Keith WL (1998) Direct measurements of turbulent boundary layer wall pressure wavenumber–frequency spectra. J Fluids Eng 120:29–39
Bokde AL, Lueptow RM, Abraham BA (1999) Spanwise structure of wall pressure on a cylinder in axial flow. Phys Fluids 11(1):151–161
Bull MK (1967) Wall-pressure fluctuations associated with subsonic turbulent boundary layer flow. J Fluid Mech 28(4):719–754
Burdic WS (1984) Underwater acoustic system analysis. Prentice-Hall, Englewood Cliffs
Carey GF, Chlupsa JE, Schloemer HH (1967) Acoustic turbulent water flow tunnel. J Acoust Soc Am 41(2):373–379
Cipolla KM, Keith WL (2003a) Momentum thickness measurements for thick axisymmetric turbulent boundary layers. J Fluids Eng 125:569–575
Cipolla KM, Keith WL (2003b) High Reynolds number thick axisymmetric turbulent boundary layer measurements. Exp Fluids 35(5):477–485
Cipolla KM, Keith WL (2008) Measurements of the wall pressure spectra on a full scale experimental towed array. Ocean Eng 35:1052–1059
Cipolla KM, Keith WL, Furey DA (2006) Investigation of the near wall pressure spectra and near field flow velocity on a full scale TB-29 towed array. In: Proceeding of the 26th symposium on naval hydrodynamics, Rome, Italy
Coles D (1953) Measurements in the boundary layer on a smooth flat plate in supersonic flow. Report no. 20-69, California Institute of Technology, Jet Propulsion Laboratory, Pasadena, CA, June 1, 1953
Corcos GM (1963) Resolution of pressure in turbulence. J Acoust Soc Am 35(2):192–199
Farabee TM, Casarella MJ (1991) Spectral features of wall pressure fluctuations beneath turbulent boundary layers. Phys Fluids A 3(10):2410–2420
Furey D, Atsavapranee P, Cipolla K (2004) Investigation of the turbulent boundary layer flow on a microfilament array. In: proceedings of 25th symposium on naval hydrodynamics, St. John’s, Canada, 8–13 August 2004
Keith WL, Barclay JJ (1993) Effects of a large eddy breakup device on the fluctuating wall pressure field. J Fluids Eng 115(3):389–397
Keith WL, Bennett JC (1991) Correction of wall pressure fluctuation measurements with a view to hydrodynamic applications. In: Forum on turbulent flows, Proceedings of ASME-JSME fluids engineering conference, Portland Oregon, 24–28 June 1991
Keith WL, Bennett JC (1991b) Low frequency measurements of wall shear stress and wall pressure in a turbulent boundary layer. J AIAA 29(4):526–530
Keith WL, Hurdis DH, Abraham BA (1992) A comparison of turbulent boundary layer wall-pressure spectra. J Fluids Eng 114:338–347
Keith WL, Cipolla KM, Hart DR, Furey DA (2005) Drag measurements on long, thin cylinders at small angles and high Reynolds numbers. Exp Fluids 38(4):759–769
Lueptow RM (1988) Turbulent boundary layer on a cylinder in axial flow. NUSC Technical Report 8389, Naval Underwater Systems Center, New London, CT, 29 September
Luxton RE, Bull MK, Rajagopalan S (1984) The thick axisymmetric boundary layer on a long fine cylinder in axial flow. Aeronaut J 88:186–199
Nepomuceno HG, Lueptow RM (1997) Pressure and shear stress measurements at the wall in a turbulent boundary layer on a cylinder. Phys Fluids 9(9):2732–2739
Snarski SR, Lueptow RM (1995) Wall pressure and coherent structures in a turbulent boundary layer on a cylinder in axial flow. J Fluid Mech 286:137–171
Willmarth WW, Yang CS (1970) Wall pressure fluctuations beneath turbulent boundary layers on a flat plate and a cylinder. J Fluid Mech 41(1):47–80
Willmarth WW, Winkel RE, Sharma LK, Bogar TJ (1976) Axially symmetric turbulent boundary layers on cylinders: mean velocity profiles and wall pressure fluctuations. J Fluid Mech 76(1):35–64
Acknowledgments
Funding was provided by the Naval Undersea Warfare Center Division Newport In-House Laboratory Independent Research (ILIR) Program, manager Mr. Richard Philips. Professor Tim Wei at RPI provided many helpful suggestions. The authors are also grateful to Ms. Jane Leous (Cornell University) and Ms. Elizabeth Scales (Georgia Tech.) for their contributions to this project under the Office of Naval Research Naval Research Enterprise Intern Program (NREIP). Mr. David Jasinski of Code 1513 also provided invaluable support on the tests.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Keith, W.L., Cipolla, K.M. & Furey, D. Turbulent wall pressure fluctuation measurements on a towed model at high Reynolds numbers. Exp Fluids 46, 181–189 (2009). https://doi.org/10.1007/s00348-008-0552-y
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00348-008-0552-y