Cross-correlation measurements in a turbulent boundary layer above a rough wall

Bessem, J. M.; Stevens, L.J.

doi:10.1063/1.864893

Cited by 11 publications

(5 citation statements)

References 4 publications

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“…Brown and Thomas (1977) crosscorrelated signals from a wall probe with u signals in a smoothwall boundary layer, finding that the maximum correlation occurred along a line in the xz plane sloping obliquely with the flow at an angle of about 18° to the horizontal. Comparable rough-wall data have been obtained by Bessem and Stevens (1984) and Osaka et al (1984), over "k-type" and "d-type" walls, respectively; in both cases, the locus of maximum u correlation was similar to that found by Brown and Thomas.…”

Section: Organized Motion In Rough-wall Boundary Layerssupporting

confidence: 66%

Rough-Wall Turbulent Boundary Layers

Raupach

Antonia

Rajagopalan

1991

Applied Mechanics Reviews

1,131

699

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This review considers theoretical and experimental knowledge of rough-wall turbulent boundary layers, drawing from both laboratory and atmospheric data. The former apply mainly to the region above the roughness sublayer (in which the roughness has a direct dynamical influence) whereas the latter resolve the structure of the roughness sublayer in some detail. Topics considered include the drag properties of rough surfaces as functions of the roughness geometry, the mean and turbulent velocity fields above the roughness sublayer, the properties of the flow close to and within the roughness canopy, and the nature of the organized motion in rough-wall boundary layers. Overall, there is strong support for the hypothesis of wall similarity: At sufficiently high Reynolds numbers, rough-wall and smooth-wall boundary layers have the same turbulence structure above the roughness (or viscous) sublayer, scaling with height, boundary-layer thickness, and friction velocity.

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Section: Organized Motion In Rough-wall Boundary Layerssupporting

confidence: 66%

Rough-Wall Turbulent Boundary Layers

Raupach

Antonia

Rajagopalan

1991

Applied Mechanics Reviews

1,131

699

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“…The outer-layer structural consistency between smooth-and rough-wall flow observed by Bessm & Stevens (1984) is in accordance with the many aforementioned studies that support the proposition of outer-layer similarity in the turbulence statistics for rough-wall turbulence. In support of this similarity, many other studies have observed little difference in the spatial velocity correlations of smooth-and rough-wall flow outside the roughness sublayer.…”

Section: Roughness Effects In the Outer Layersupporting

confidence: 76%

“…Bessm & Stevens (1984) studied the inclination angle of large-scale structures in a turbulent boundary layer over a k-type grooved surface via measurements of the cross-correlation between the wall shear stress and streamwise velocity for 0.05 < y/J < 0.75. An inclination angle of approximately 20' was observed which is consistent with the results of Brown & Thomas (1977) and Head & Bandyopadhyay (1981) for smooth-wall turbulence.…”

Section: Roughness Effects In the Outer Layermentioning

confidence: 99%

Studies of Real Roughness Effects for Improved Modeling and Control of Practical Wall-Bounded Turbulent Flows

Christensen¹,

Wu²

2008

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The public reporting burden for this collection of information is estimated to average 1 hour per response. including the time for reviewing instructions, sea"hing existing data soUrces, gathering and maintaining the data needed, and completing and reviewving the collection of infomation. Send comments regaliong this burden estimate or any otiler aspect of tts collection of information. including suggestions for reducing fhe burden, to the Department of Defense, Executive Service Directorate (0704-0188). Respondents should be aware that notwithstanding any other provision of law. no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a curently valid OMB control number. PLEASE DO NOT RETURN YOUR A F R L S R SUPPLEMENTARY NOTES ABSTRACTThe present effort investigates the effects of practical roughness replicated from a turbine blade damaged by deposition of foreign material. statistical and structural characteristics of wall turbulence. Two-dimensional particle image velocimetry (PIV) measurements are performed in the streamwise-wall-normal plane of turbulent boundary layers at momentum Reynolds numbers of 8000 and 13000. The surface conditions include a smooth wall and two highly-irregular rough walls. These rough surfaces have the same roughness topography but differ in spatial scaling. The validity of Townsend's wall similarity hypothesis in the presence of practical roughness is assessed and the impact of this roughness on the spatial structure of the flow is investigated. In addition, stereoscopic PIV measurements are made in streamwise-spanwise planes of smooth-and rough-wall turbulent boundary layers both within and at the outer edge of the roughness sublayer. This data is used to explore the impact of dominant topographical features on the near-wall flow as well as the influence of practical roughness on the spatial organization of the flow.Understanding such effects provides a stepping stone toward efficient modeling and control of practical flows in the presence of roughness. SUBJECT TERMS

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“… Gurnett et al [1983] cite laboratory experiments in developing methods of recognizing the presence of dust grains near Saturn [ Adams and Smith , 1971; Friichtenicht , 1964; Grün , 1981]. LaBelle and Kintner [1989], in discussing the measurement of wavelength in space plasmas, point to the routine use of cross‐correlation analysis in laboratory experiments [ Gresillon and Doveil , 1975; Gresillon et al , 1975; Bessem and Stevens , 1984].…”

Section: Laboratory Results Cited By Space Researchersmentioning

confidence: 99%

“…Langmuir probes [ Mott‐Smith and Langmuir , 1926] have evolved into floating‐bias probes for measuring DC [ Smith et al , 1979] and AC [ Sprott , 1966] values of electrostatic (“space”) potential, swept‐bias probes for determining electron temperature from the functional form of collected current versus bias, fixed‐bias probes for inferring plasma density and its fluctuations from the DC and AC values of collected current, and single‐sided probes for directional analysis of velocity distribution functions. Cross‐correlation analysis for coordinate space was developed by Gresillon and Doveil [1975], Gresillon et al [1975], and Bessem and Stevens [1984]. Cross‐spectral analysis for the frequency domain was developed by Harker and Ilić [1974] and Ilić [1975].…”

Section: Benefits Of Laboratory Experiments To the Understanding Of Smentioning

confidence: 99%

Interrelated laboratory and space plasma experiments

Koepke

2008

Reviews of Geophysics

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[1] Many advances in understanding space plasma phenomena have been linked to insight derived from theoretical modeling and/or laboratory experiments. Advances for which laboratory experiments played an important role are reviewed here. How the interpretation of the space plasma data was influenced by one or more laboratory experiments is described. The space physics motivation of laboratory investigations and the scaling of laboratory plasma parameters to space plasma conditions are discussed. Examples demonstrating how laboratory experiments develop physical insight, validate or invalidate theoretical models, discover unexpected behavior, establish observational signatures, and pioneer diagnostic methods for the space community are presented. The various device configurations found in space-related laboratory investigations are outlined. A primary objective of this review is to articulate the overlapping scientific issues that are addressable in space and laboratory experiments. A secondary objective is to convey the wide range of laboratory and space plasma experiments involved in this interdisciplinary alliance. Over time the degree to which the interrelated experiments can be compared has increased, thanks to improved diagnostic techniques in space and closer attention to matching dimensionless space parameters in the laboratory.

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Cross-correlation measurements in a turbulent boundary layer above a rough wall

Abstract: Cross correlation between signals from a wall probe and a hot-wire probe indicates that large structures, inclined to the wall at approximately 20 °, exist in a rough-wall boundary layer as reported earlier by Brown and Thomas and by Head and Bandyopadhyay for a smooth wall.

Cited by 11 publications

References 4 publications

Rough-Wall Turbulent Boundary Layers

Rough-Wall Turbulent Boundary Layers

Studies of Real Roughness Effects for Improved Modeling and Control of Practical Wall-Bounded Turbulent Flows

Interrelated laboratory and space plasma experiments

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