Turbulent boundary layers on axially inclined cylinders. Part 1. Surface-pressure/velocity correlations

Heenan, A.F.; Morrison, J. F.

doi:10.1007/s00348-001-0384-5

Cited by 12 publications

(8 citation statements)

References 18 publications

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“…Presently we do not have any conclusive explanations for this. One possibility is that during non-optimal weather, cross-flow and vortex shedding strip away parts of the TBL from the streamer, (Heenan and Morrison, 2002b) and (Heenan and Morrison, 2002a). Turbulent structures that normally would be responsible for the noise generation in this particular frequency range are therefore less common, and we get a reduced level of noise.…”

Section: From 15-55 Hzmentioning

confidence: 99%

“…For a cylindrical geometry the turbulent structures are not bounded in the span-wise direction, and are free to move around the streamer. The result of this has been summed up in Heenan and Morrison (2002a), where they found that for a cylindrical geome- try, the Reynolds stresses u i u j and the shear stress τ w tend to be larger close to the surface, and smaller further away from the surface compared to the flat plate case. This is relevant for flow noise generation through Equation 5.2.…”

Section: The Acoustic Source Termmentioning

confidence: 99%

“…For example, competing scaling relations for the mean-velocity profile near the cylinder wall have been proposed by Afzal and Narasimha (1976), Denli and Landweber (1979), and Lueptow et al (1985) amongst others. Both Lueptow et al (1985), and Heenan and Morrison (2002a), as well as a number of other researchers have shown that even a small misalignment of the axis of a cylinder relative to the mean flow will cause asymmetry of the boundary layer. This will induce significant deviations in the fluctuating wall pressure levels around the circumference of the cylinder.…”

Section: Previous Workmentioning

confidence: 99%

“…These disturbances probably make a significant contributions to the fluctuating rms-pressure near a cylinder surface. Both Lueptow et al (1985), and Heenan and Morrison (2002a), as well as a number of other researchers have shown that even small misalignments of the axis of the cylinder relative to the mean flow will cause asymmetry of the boundary layer and induce significant deviations in the fluctuating wall pressure levels around the circumference of the cylinder. Based on measurements, Lueptow et al (1985), and Furey (2005) provide statistics on the distribution of the Reynolds stresses within the turbulent boundary layer at α = 0…”

Section: Literature and Fluid Mechanical Backgroundmentioning

confidence: 99%

“…Neves and Moin (1994a,b) conducted numerical simulations of axial flow and presented detailed turbulence statistics. Lueptow et al (1985), Heenan and Morrison (2002a), and a number of other researchers, have shown that even small misalignments of the axis of the cylinder relative to the mean towing direction will cause asymmetry of the boundary layer. As a result the fluctuating wall pressure levels around the cylinder are significantly modified.…”

Section: Previous Workmentioning

confidence: 99%

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Flow and swell noise in marine seismic data

2009

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Various weather-related mechanisms for noise generation during marine seismic acquisition were addressed from a fluid-dynamic perspective. This was done by analyzing a number of seismic lines recorded on modern streamers during nonoptimal weather conditions. In addition, we examined some of the complex fluid-mechanics processes associated with flow that surrounds seismic streamers. The main findings were that noise in the [Formula: see text] range is mostly the result of direct hydrostatic-pressure fluctuations on the streamer caused by wave motion. For normal swell noise above [Formula: see text] and for crossflow noise, a significant portion of the observed noise probably comes from dynamic fluctuations caused by the interaction between the streamer and fluid structures in its turbulent boundary layer. This explanation differs from most previous work, which has focused on streamer oscillations, bulge waves inside old fluid-filled seismic streamers, or strumming/tugging as the main source of weather-related noise. Although modern streamers are less sensitive to such sources of noise, their ability to tackle the influence on turbulent flow noise has not improved. This implies that noise induced by turbulent flow has increased its relative impact on modern equipment. To improve the signal-to-noise ratio on seismic data, design issues related to flow noise must be addressed.

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Section: From 15-55 Hzmentioning

confidence: 99%

Section: The Acoustic Source Termmentioning

confidence: 99%