Wall pressure fluctuations in attached boundary-layer flow

Laganelli, A. L.; Martellucci, A.; Shaw, Leonard

doi:10.2514/3.8105

Cited by 79 publications

(22 citation statements)

References 12 publications

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“…This value, albeit lower than Kistler and Chan's 14 value, is in good agreement with that found by Speaker and Ailman, 15 Chyu and Hanly, 16 Coe, 6 and Laganelli et al 17 As reported in previous studies, 8 the probability density distribution of p w ' is essentially Gaussian, with skewness and flatness factors of 0.05 and 3.05, respectively. Figure 2 shows the space-time correlation of the fluctuating wall pressure R pp (^760,0,7) in the incoming boundary layer.…”

Section: Incoming Turbulent Boundary Layersupporting

confidence: 92%

Unsteady nature of shock-wave/turbulent boundary-layer interaction

1988

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This study addresses the unsteady aspect of shock-wave/turbulent boundary-layer interaction. The interaction was generated using a two-dimensional compression ramp at a freestream Mach number of 2.9. Three models were tested, with flow conditions ranging from fully separated to incipient separation. An array of flushmounted, miniature, high-frequency pressure transducers was used to make multichannel measurements of the fluctuating wall pressure within the interaction. The present results show that, upstream of the mean separation line, the flow is dominated by the large-scale "flapping" motions of a single sharp shock wave. Instantaneously, this shock front is considerably spanwise nonuniform, giving it a "rippling" appearance. In the separated region, however, convective turbulence phenomena play a much larger role. The energy containing turbulent eddies above the recirculation zone and traveling in the downstream direction appear to be the major contributors to the wall pressure fluctuations. Here, the time scale of the pressure signals is found to decrease significantly as the shock strength is increased.

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Section: Incoming Turbulent Boundary Layersupporting

confidence: 92%

Unsteady nature of shock-wave/turbulent boundary-layer interaction

1988

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“…Some correlations exist for the magnitude of transitional and turbulent pressure fluctuations, but these were derived primarily using either incompressible data or conventional (noisy flow) hypersonic wind-tunnel tests. 1 Such modeling efforts have not led to sufficient physical understanding of the transitional pressure fluctuations or to adequate predictive capabilities. Modern computational capabilities seem likely to enable higher-fidelity models in the future.…”

Section: Introductionmentioning

confidence: 99%

High-Speed Schlieren Imaging of Disturbances in a Transitional Hypersonic Boundary Layer

Casper

Beresh

Henfling

et al. 2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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A high-speed schlieren system was developed for the Sandia Hypersonic Wind Tunnel. Schlieren images were captured at 290 kHz and used to study the growth and breakdown of second-mode instabilities into turbulent spots on a 7 • cone. At Mach 5, wave packets would intermittently occur and break down into isolated turbulent spots surrounded by an otherwise smooth, laminar boundary layer. At Mach 8, the boundary layer was dominated by second-mode instabilities which would break down into larger regions of turbulence. Second-mode waves surrounded these turbulent patches as opposed to the smooth laminar flow seen at Mach 5.Detailed pressure and thermocouple measurements were also made along the cone at Mach 5, 8 and 14, in a separate tunnel entry. These measurements give an average picture of the transition behavior that complements the intermittent behavior captured by the schlieren system. At Mach 14, the boundary-layer remained laminar so the transition process could not be studied. However, the first measurements of second-mode waves were made in HWT-14. Nomenclatureδ boundary-layer thickness (mm) φ cone azimuthal angle ( • ) τ w nozzle wall shear stress (Pa) D model base diameter (m) M freestream Mach number M e Mach number at boundary-layer edge P 0 tunnel stagnation pressure (kPa) p root-mean-square pressure fluctuation (Pa) p pressure fluctuation, p − p e (Pa) p e boundary-layer edge pressure (Pa) q e dynamic pressure at boundary-layer edge (Pa) R cone radius (mm) Re freestream unit Reynolds number (1/m) Re D freestream Reynolds number based on model base diameter St Stanton number T 0 tunnel stagnation temperature (K) U c average convection velocity (m/s) U e boundary-layer edge velocity (m/s) x axial model coordinate measured from nose (m)

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“…Large scatter in the data was observed, which was mainly attributed to limitations in the frequency response of pressure sensors and led those authors to shed doubts on the reliability of many semi-empirical engineering models developed for the prediction of the wall pressure fluctuations, [17][18][19] which rely heavily on the accuracy of experimental measurements. By merging signals from multiple sensors, Beresh et al 16 measured frequency spectra of the wall pressure, which were corrected for spatial attenuation at high frequencies and for wind-tunnel noise and vibrations at low frequencies.…”

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confidence: 95%

Wall pressure fluctuations beneath supersonic turbulent boundary layers

2011

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The structure of the wall pressure field beneath supersonic adiabatic turbulent boundary layers is analyzed by means of direct numerical simulations at free-stream Mach number M(infinity) = 2, 3, 4, spanning a relatively large range of Reynolds numbers. The data reported in the paper, which include wall pressure fluctuations intensities, frequency spectra, space-time correlations, and convection velocities, show that when pressure is scaled by the wall shear stress, most statistics well conform to low-speed findings, contradicting the conclusions of previous experimental studies. Genuine compressibility effects are found to provide a small contribution to the magnitude of the wall pressure fluctuations, their influence being limited to the high-frequency end of the spectra, where a systematic increase with the Mach number is observed. (C) 2011 American Institute of Physics. [doi:10.1063/1.3622773

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Wall pressure fluctuations in attached boundary-layer flow

Cited by 79 publications

References 12 publications

Unsteady nature of shock-wave/turbulent boundary-layer interaction

Unsteady nature of shock-wave/turbulent boundary-layer interaction

High-Speed Schlieren Imaging of Disturbances in a Transitional Hypersonic Boundary Layer

Wall pressure fluctuations beneath supersonic turbulent boundary layers

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