Drag measurements on long thin cylinders at small angles and high Reynolds numbers

Keith, William L.; Cipolla, Kimberly; Hart, David R.; Furey, Deborah

doi:10.1007/s00348-005-0959-7

Cited by 12 publications

(7 citation statements)

References 11 publications

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“…In Cipolla and Keith (2003) and Keith et al (2005) details on how boundary layer thickness scale with the cylinder length are presented. Reviews of much of the early work done on wall pressure fluctuations can be found in Bull (1996) and in Snarski (1993).…”

Section: Literature and Fluid Mechanical Backgroundmentioning

confidence: 99%

Attenuation of noise in marine seismic data

Elboth

Geoteam

Hermansen

2009

SEG Technical Program Expanded Abstracts 2009

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Section: Literature and Fluid Mechanical Backgroundmentioning

confidence: 99%

Attenuation of noise in marine seismic data

Elboth

Geoteam

Hermansen

2009

SEG Technical Program Expanded Abstracts 2009

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“…While it is possible to measure drag on some sets of gear (e.g., van der Hoop et al, 2013bHoop et al, , 2015, drag forces can also be estimated from wellestablished physical theory (Fridman, 1986;Faltinsen, 1993;Helmond, 2001;Keith et al, 2004). To determine the relationship between measured and theoretical drag forces, both methods were applied to sets of fishing gear that had entangled or are similar to those entangling right whales.…”

Section: Introductionmentioning

confidence: 99%

Effects of added drag on cetaceans : fishing gear entanglement and external tag attachment

Hoop¹

2017

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Animal movement is motivated in part by energetic constraints, where fitness is maximized by minimizing energy consumption. The energetic cost of movement depends on the resistive forces acting on an animal; changes in this force balance can occur naturally or unnaturally. Fishing gear that entangles large whales adds drag, often altering energy balance to the point of terminal emaciation. An analog to this is drag from tags attached to cetaceans for research and monitoring. This thesis quantifies the effects of drag loading from these two scenarios on fine-scale movements, behaviors and energy consumption.I measured drag forces on fishing gear that entangled endangered North Atlantic right whales and combined these measurements with theoretical estimates of drag on whales' bodies. Entanglement in fishing gear increased drag forces by up to 3 fold. Bio-logging tags deployed on two entangled right whales recorded changes in the diving and fine-scale movement patterns of these whales in response to relative changes in drag and buoyancy from fishing gear and through disentanglement: some swimming patterns were consistently modulated in response. Disentanglement significantly altered dive behavior, and can affect thrust production. Changes in the force balance and swimming behaviors have implications for the survival of chronically entangled whales. I developed two bioenergetics approaches to estimate that chronic, lethal entanglements cost approximately the same amount as the cost of pregnancy and supporting a calf to near-weaning. I then developed a method to estimate drag, energy burden and survival of an entangled whale at detection. This application is essential for disentanglement response and protected species management.Experiments with tagged bottlenose dolphins suggest similar responses to added drag: I determined that instrumented animals slow down to avoid additional energetic costs associated with drag from small bio-logging tags, and incrementally decrease swim speed as drag increases. Metabolic impacts are measurable when speed is constrained. I measured the drag forces on these tags and developed guidelines depending on the relative size of instruments to study-species.Together, these studies quantify the magnitude of added drag in complementary systems, and demonstrate how animals alter their movement to navigate changes in their energy landscape associated with increased drag.

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“…Experiments and theory developed by Keith et al (2005) and Furey (2005) show that streamers are surrounded by a turbulent boundary layer that grows from a few millimeters near the front to perhaps several decimeters near the tail, depending on the length of the streamer. In addition, a streamer is subjected to sea motion from waves and currents.…”

Section: Weather Noise Generationmentioning

confidence: 99%

“…Turbulent kinetic energy, for instance, is defined as k = (u 2 + v 2 + w 2 )/2. In Cipolla and Keith (2003) and Keith et al (2005) details on how boundary layer thickness scale with the cylinder length are presented. Reviews of much of the early work done on wall pressure fluctuations can be found in Bull (1996) and in Snarski (1993).…”

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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Drag measurements on long thin cylinders at small angles and high Reynolds numbers

Cited by 12 publications

References 11 publications

Attenuation of noise in marine seismic data

Attenuation of noise in marine seismic data

Effects of added drag on cetaceans : fishing gear entanglement and external tag attachment

Flow and swell noise in marine seismic data

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