A nearly isotropic turbulence generated by a pair of vibrating grids

Shy, S.S.; Tang, C.Y.; Fann, Shin

doi:10.1016/s0894-1777(96)00111-2

Cited by 60 publications

(49 citation statements)

References 12 publications

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“…Unlike tanks with a single stirring grid (e.g. Hopfinger and Toly, 1976;Brumley and Jirka, 1987), tanks with two stirring grids produce turbulence that is homogeneous and nearly isotropic in a large region centered between the two grids (Srdic et al, 1996;Shy et al, 1997).…”

Section: Turbulence Experimentsmentioning

confidence: 99%

Active downward propulsion by oyster larvae in turbulence

Fuchs

Hunter

Schmitt

et al. 2012

Journal of Experimental Biology

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SUMMARYOyster larvae (Crassostrea virginica) could enhance their settlement success by moving toward the seafloor in the strong turbulence associated with coastal habitats. We characterized the behavior of individual oyster larvae in grid-generated turbulence by measuring larval velocities and flow velocities simultaneously using infrared particle image velocimetry. We estimated larval behavioral velocities and propulsive forces as functions of the kinetic energy dissipation rate ε, strain rate γ, vorticity ξ and acceleration α. In calm water most larvae had near-zero vertical velocities despite propelling themselves upward (swimming). In stronger turbulence all larvae used more propulsive force, but relative to the larval axis, larvae propelled themselves downward (diving) instead of upward more frequently and more forcefully. Vertical velocity magnitudes of both swimmers and divers increased with turbulence, but the swimming velocity leveled off as larvae were rotated away from their stable, velum-up orientation in strong turbulence. Diving speeds rose steadily with turbulence intensity to several times the terminal fall velocity in still water. Rapid dives may require a switch from ciliary swimming to another propulsive mode such as flapping the velum, which would become energetically efficient at the intermediate Reynolds numbers attained by larvae in strong turbulence. We expected larvae to respond to spatial or temporal velocity gradients, but although the diving frequency changed abruptly at a threshold acceleration, the variation in propulsive force and behavioral velocity was best explained by the dissipation rate. Downward propulsion could enhance oyster larval settlement by raising the probability of larval contact with oyster reef patches.

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Section: Turbulence Experimentsmentioning

confidence: 99%

Active downward propulsion by oyster larvae in turbulence

Fuchs

Hunter

Schmitt

et al. 2012

Journal of Experimental Biology

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“…The experimental investigations on turbulence have been conducted in either a decaying homogeneous turbulence with a mean flow, such as water tunnels, or in a stationary homogeneous turbulence field with no mean flow, such as those generated by oscillating grids [8]. The former generators, however, have limited application range especially since increasing the fluid velocity is the only means to increase the intensity of the turbulence.…”

Section: Introductionmentioning

confidence: 99%

Influence of turbulence intensity on particle drag coefficients

Doroodchi

Evans

Schwarz

et al. 2008

Chemical Engineering Journal

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“…A region of approximately homogeneous and isotropic turbulence is formed between two oscillating grids (Srdic et al, 1996). It was found (Shy et al, 1997) that the length of this region is linearly proportional to the distance between the grids. Our estimations of the turbulence integral scale dependence based on data by Hopfinger and Toly (1976) vs. the distance z in a range S/M = 0.2 − 0.9 yield…”

Section: Experimental Set-upmentioning

confidence: 99%

Oscillating grids turbulence generator for turbulent transport studies

Eidelman

Elperin

Kapusta

et al. 2002

Nonlin. Processes Geophys.

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Abstract. An oscillating grids turbulence generator was constructed for studies of two new effects associated with turbulent transport of particles, turbulent thermal diffusion and clustering instability. These effects result in formation of large-scale and small-scale inhomogeneities in the spatial distribution of particles. The advantage of this experimental set-up is the feasibility to study turbulent transport in mixtures with controllable composition and unlimited observation time. For flow measurements we used Particle Image Velocimetry with the adaptive multi-pass algorithm to determine a turbulent velocity field and its statistical characteristics. Instantaneous velocity vector maps, flow streamlines and probability density function of velocity field demonstrate properties of turbulence generated in the device.

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A nearly isotropic turbulence generated by a pair of vibrating grids

Cited by 60 publications

References 12 publications

Active downward propulsion by oyster larvae in turbulence

Active downward propulsion by oyster larvae in turbulence

Influence of turbulence intensity on particle drag coefficients

Oscillating grids turbulence generator for turbulent transport studies

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