Vortex shedding from long slender cylinders in near-axial flow

Bull, M. K.; Dekkers, Willem

doi:10.1063/1.858688

Cited by 13 publications

(11 citation statements)

References 4 publications

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“…Such separation can be expected to have a particularly strong effect on the flow physics. For instance, Bull and Dekkers 14 found that for very long cylinders (L/Dϳ3000) with correspondingly very thick boundary layers, organized vortex shedding occurred down to yaw angles as little as ␣ϭ1°over a limited range of Re D . The effect of the inflow boundary layer thickness as well as the limits of the organized vortex shedding and trailing vortex regimes in the ␣ -Re D plane are not well understood.…”

Section: Introductionmentioning

confidence: 98%

Flow over yawed circular cylinders: Wall pressure spectra and flow regimes

Snarski

2003

Physics of Fluids

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The fluctuating wall pressure on a circular cylinder in cross flow has been investigated experimentally in a water tunnel to examine the effect of yaw angle on the spectral characteristics of the wall pressure field and to provide insight into the periodic and turbulent structures of the flow. Wall pressure was measured at five azimuthal positions around the periphery of the cylinder for seven yaw angles from ␣ϭ90°͑normal flow͒ to ␣ϭ0°͑axial flow͒ at three subcritical Reynolds numbers (Re D ϭ7200, 13 500, 27 600). As the yaw angle is varied from ␣ϭ90°to 0°, large systematic and nonmonotonic variations in both the narrowband ͑periodic vortex shedding͒ and broadband ͑turbulent͒ spectral levels occur. The results provide additional insight into the structural characteristics of the yawed cylinder flow regimes over that which has been identified previously through measurements of mean wall forces and flow field characteristics. Significant Reynolds number effects were also observed over the range of the measurements, particularly at small yaw angles, that may indicate fundamental shifts in the structure of the wake or underlying regime transition mechanisms. Possible effects due to vortex-induced cylinder vibrations are not entirely clear but predominantly confined to the larger yaw angles. Simultaneous wall pressure, cylinder vibration, radiated acoustic pressure, and wake velocity measurements are required to appropriately isolate the various potential contributions to the wall pressure field and thus provide a clearer understanding of the underlying boundary layer separation, transitional wake, and fluid-structural coupling mechanisms.

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Section: Introductionmentioning

confidence: 98%

Flow over yawed circular cylinders: Wall pressure spectra and flow regimes

Snarski

2003

Physics of Fluids

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“…Unsteady tugging motion by the towing system and lift from steering birds that try to maintain the streamer at a constant depth also add to the complexity of the flow environment. Experiments by Bull and Dekkers (1993), Heenan and Morrison (2002a,b) and Snarski (2004) indicate that the flow characteristics in the turbulent boundary layer surrounding long cylindrical objects like seismic streamers will change when the local angle between the streamer and the flow direction exceeds 6-15…”

Section: Weather Noise Generationmentioning

confidence: 99%

“…Cross flow can also be induced by ocean currents. Experiments by Bull and Dekkers (1993), Morrison (2002a,b), andSnarski (2004) indicate that the flow characteristics in the turbulent boundary layer surrounding long cylindrical objects like seismic streamer cables will change when the local angle between the streamer and the flow direction exceeds approximately 6…”

Section: Swell Noisementioning

confidence: 99%

“…Based on water-tank experiments, Bull and Dekkers (1993) observed that vortex shedding might occur for a limited range of Reynolds number for long cylinders (with the length to diameter ratio L/d ≈ 3000) at inclination angles as low as α = 1…”

Section: Previous Workmentioning

confidence: 99%

“…Early numerical simulations of axial flow were conducted by Neves and Moin (1994b,a) where they also present detailed turbulence statistics for axially aligned flow. Based on wind-tunnel experiments, Bull and Dekkers (1993) found that vortex shedding can occur for a limited range of Reynolds number for long cylinders (L/(2a))≈ 3000) at inclination angles as low as α = 1 • .…”

Section: Literature and Fluid Mechanical Backgroundmentioning

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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High Reynolds number thick axisymmetric turbulent boundary layer measurements

Cipolla

Keith

2003

Experiments in Fluids

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Vortex shedding from long slender cylinders in near-axial flow

Cited by 13 publications

References 4 publications

Flow over yawed circular cylinders: Wall pressure spectra and flow regimes

Flow over yawed circular cylinders: Wall pressure spectra and flow regimes

Flow and swell noise in marine seismic data

High Reynolds number thick axisymmetric turbulent boundary layer measurements

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