Joint probabilities and mixing of isolated scalars emitted from parallel jets

Soltys, Michael; Crimaldi, John P.

doi:10.1017/jfm.2015.113

Cited by 20 publications

(14 citation statements)

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“…Segregating an unknown odorant from a mixture is a blind source separation problem, and solving it requires more information than just the chemical odorant identity (Hendin et al, 1994). The physics of odorant dispersion adds relational information to the chemical odorant identity, as odorants from the same source form plumes with relatively stable odorant concentration proportions (homogeneous plumes), while odorants from different sources form plumes with variable odorant concentration proportions (heterogeneous plumes; Hopfield, 1991; Kree et al, 2013; Celani et al, 2014; Riffell et al, 2014; Soltys and Crimaldi, 2015; Erskine et al, 2019). Indeed, animals can use these relational stimuli to detect whether odorants originate from the same or different sources.…”

Section: Discussionmentioning

confidence: 99%

“…Natural olfactory stimuli are typically mixtures of many different odorants from different sources, which mix together in turbulent plumes (Murlis et al, 1992; Kree et al, 2013; Celani et al, 2014; Riffell et al, 2014; Soltys and Crimaldi, 2015; Erskine et al, 2019). Previous studies suggested that animals perceive odorant mixtures synthetically, that is, they perceive a mixture as a perceptual unit rather than as a list of individual odorants (humans: Jinks and Laing, 1999; squirrel monkeys: Laska and Hudson, 1993; rats: Staubli et al, 1987; spiny lobsters: Lynn et al, 1994, honey bees: Chandra and Smith, 1998; Smith, 1998; Deisig et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

“…Due to the turbulent structure of plumes, odorants that originate from the same source fluctuate with stable relative concentration proportions, forming a homogeneous stream of plumes, whereas odorants from different sources will have varying relative concentration proportions, creating a heterogeneous stream of plumes (Hopfield, 1991; Kree et al, 2013; Celani et al, 2014; Riffell et al, 2014; Soltys and Crimaldi, 2015; Erskine et al, 2019). Therefore, homogeneous and heterogeneous plumes could provide the animal with information about the number of odor sources and which odorants belong to the same odor source.…”

Section: Introductionmentioning

confidence: 99%

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Segregation of Unknown Odors From Mixtures Based on Stimulus Onset Asynchrony in Honey Bees

Sehdev

Szyszka

2019

Front. Behav. Neurosci.

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Animals use olfaction to search for distant objects. Unlike vision, where objects are spaced out, olfactory information mixes when it reaches olfactory organs. Therefore, efficient olfactory search requires segregating odors that are mixed with background odors. Animals can segregate known odors by detecting short differences in the arrival of mixed odorants (stimulus onset asynchrony). However, it is unclear whether animals can also use stimulus onset asynchrony to segregate odorants that they had no previous experience with and which have no innate or learned relevance (unknown odorants). Using behavioral experiments in honey bees, we here show that stimulus onset asynchrony also improves segregation of those unknown odorants. The stimulus onset asynchrony necessary to segregate unknown odorants is in the range of seconds, which is two orders of magnitude larger than the previously reported stimulus asynchrony sufficient for segregating known odorants. We propose that for unknown odorants, segregating odorant A from a mixture with B requires sensory adaptation to B.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Segregation of Unknown Odors From Mixtures Based on Stimulus Onset Asynchrony in Honey Bees

Sehdev

Szyszka

2019

Front. Behav. Neurosci.

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confidence: 90%

Effect of instantaneous stirring process on mixing between initially distant scalars in turbulent obstacle wakes

Shoaei

Crimaldi

2017

Exp Fluids

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and experimentally (Soltys and Crimaldi 2015). This scalar coalescence occurs even for passive scalars where the dynamics of each scalar field evolves independently of the other; the structure of the shared velocity field is responsible for the coalescence. If the initial separation distance between the two scalars is smaller than the largest coherent length scales of the local flow, the two scalar fields develop similar instantaneous spatial distributions. While it is easier to envision these processes in simple flows, recent numerical simulations (Pratt et al. 2015) have shown that in more complex 2D flows involving multiple interacting vortices, initially distant scalars coalesce in regions of intense mixing and attracting Lagrangian coherent structures.In aquatic ecosystems, structured flows can facilitate stirring and diffusion to enhance reactions or population growth by bringing together species and nutrients (e.g., Richards and Brentnall 2006). Structured flows stir any introduced scalars into thin filament shells (Garrett 1983), enhancing local scalar gradients, increasing the interfacial area of the scalar through chaotic stretching and folding (Hinch 1999), leading finally to increased mixing by molecular diffusion.Structured flow can also contribute directly to the colocation of conspecifics or species competing for a resource (e.g., Károlyi et al. 2000). The presence of benthic aquatic fauna can itself lead to structured flow in wakes downstream of the organisms. Flow structure is also modified by benthic topology such as sea-mounts, and can be dominated by a vortex wake that produces mixing (Richards 1990). As a specific example, these stirring mechanisms may enhance fertilization rates for reproduction by benthic marine invertebrates, which reproduce by broadcast spawning: plumes of egg and sperm are released, at separate locations, into Abstract A two-channel planar laser-induced fluorescence technique is used to study mixing and reactions between two initially distant scalars in the turbulent wake of a cylindrical obstacle. The scalars are released continuously and isokinetically upstream of the cylinder, with a lateral separation that initially impedes mixing between them. The effect of the turbulent wake on mixing and reaction enhancement is determined by measuring the segregation parameter for cases with and without the cylinder obstruction. Results indicate that scalar mixing and reaction rates (in the low-Damkohler limit) increase significantly in the presence of the cylinder wake. The study also shows that the dominant contribution of total reaction derives from the scalar covariance associated with instantaneous flow processes, and depends strongly on streamwise location within the wake. The results have broad implications for mixing processes in engineering and ecology.

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“…Both numerical 14,15 and experimental 16 studies have shown that the stirring of initially distant scalars may result in their eventual overlap. When the concentration of the filaments is not too low, these coalescence events have been shown to lead to reaction rates much greater than would be predicted by a well-mixed system, a process that we refer to as reaction enhancement.…”

Section: A Enhanced Reaction Of Initially Distant Scalarsmentioning

confidence: 99%

Reaction enhancement of initially distant scalars by Lagrangian coherent structures

2015

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Turbulent fluid flows have long been recognized as a superior means of diluting initial concentrations of scalars due to rapid stirring. Conversely, experiments have shown that the structures responsible for this rapid dilution can also aggregate initially distant reactive scalars and thereby greatly enhance reaction rates. Indeed, chaotic flows not only enhance dilution by shearing and stretching but also organize initially distant scalars along transiently attracting regions in the flow. To show the robustness of this phenomenon, a hierarchical set of three numerical flows is used: the periodic wake downstream of a stationary cylinder, a chaotic double gyre flow, and a chaotic, aperiodic flow consisting of interacting Taylor vortices. We demonstrate that Lagrangian coherent structures (LCS), as identified by ridges in finite time Lyapunov exponents, are directly responsible for this coalescence of reactive scalar filaments. When highly concentrated filaments coalesce, reaction rates can be orders of magnitude greater than would be predicted in a well-mixed system. This is further supported by an idealized, analytical model that was developed to quantify the competing e↵ects of scalar dilution and coalescence. Chaotic flows, known for their ability to e ciently dilute scalars, therefore have the competing e↵ect of organizing initially distant scalars along the LCS at timescales shorter than that required for dilution, resulting in reaction enhancement. C 2015 AIP Publishing LLC. [http://dx.

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Joint probabilities and mixing of isolated scalars emitted from parallel jets

Cited by 20 publications

References 70 publications

Segregation of Unknown Odors From Mixtures Based on Stimulus Onset Asynchrony in Honey Bees

Segregation of Unknown Odors From Mixtures Based on Stimulus Onset Asynchrony in Honey Bees

Effect of instantaneous stirring process on mixing between initially distant scalars in turbulent obstacle wakes

Reaction enhancement of initially distant scalars by Lagrangian coherent structures

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