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Sanjoy Banerjee - One of the best experts on this subject based on the ideXlab platform.
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Particle behavior in the turbulent boundary layer ii velocity and distribution profiles
Physics of Fluids, 1995Co-Authors: D Kaftori, G Hetsroni, Sanjoy BanerjeeAbstract:The velocity, Flux, and concentration distribution of solid Particles in a turbulent boundary layer of a horizontal water flume were investigated experimentally by means of LDA and visualization techniques. The Particles were of polystyrene (specific density ∼1.05). Results show that coherent wall structures are responsible for most of the characteristics of Particle behavior throughout the boundary layer. Particles are often concentrated in regions of low velocity, associated with wall structures, and as a result the average Particle velocity is lower than the fluid’s. This was also noted previously by Rashidi et al., but not explained. The actual relative velocity between the Particles and the surrounding fluid is often small. In addition, the data suggest that as the shear rate increases, the Particle Flux profiles asymptotically approach a shape where a strong gradient of Particle Flux exists in the lower part of the boundary layer (y+≤250), while it is relatively constant at higher elevations. This p...
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Particle behavior in the turbulent boundary layer ii velocity and distribution profiles
Physics of Fluids, 1995Co-Authors: D Kaftori, G Hetsroni, Sanjoy BanerjeeAbstract:The velocity, Flux, and concentration distribution of solid Particles in a turbulent boundary layer of a horizontal water flume were investigated experimentally by means of LDA and visualization techniques. The Particles were of polystyrene (specific density ∼1.05). Results show that coherent wall structures are responsible for most of the characteristics of Particle behavior throughout the boundary layer. Particles are often concentrated in regions of low velocity, associated with wall structures, and as a result the average Particle velocity is lower than the fluid’s. This was also noted previously by Rashidi et al., but not explained. The actual relative velocity between the Particles and the surrounding fluid is often small. In addition, the data suggest that as the shear rate increases, the Particle Flux profiles asymptotically approach a shape where a strong gradient of Particle Flux exists in the lower part of the boundary layer (y+≤250), while it is relatively constant at higher elevations. This phenomenon may also be attributable to interactions with the wall structures.
D Kaftori - One of the best experts on this subject based on the ideXlab platform.
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Particle behavior in the turbulent boundary layer ii velocity and distribution profiles
Physics of Fluids, 1995Co-Authors: D Kaftori, G Hetsroni, Sanjoy BanerjeeAbstract:The velocity, Flux, and concentration distribution of solid Particles in a turbulent boundary layer of a horizontal water flume were investigated experimentally by means of LDA and visualization techniques. The Particles were of polystyrene (specific density ∼1.05). Results show that coherent wall structures are responsible for most of the characteristics of Particle behavior throughout the boundary layer. Particles are often concentrated in regions of low velocity, associated with wall structures, and as a result the average Particle velocity is lower than the fluid’s. This was also noted previously by Rashidi et al., but not explained. The actual relative velocity between the Particles and the surrounding fluid is often small. In addition, the data suggest that as the shear rate increases, the Particle Flux profiles asymptotically approach a shape where a strong gradient of Particle Flux exists in the lower part of the boundary layer (y+≤250), while it is relatively constant at higher elevations. This p...
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Particle behavior in the turbulent boundary layer ii velocity and distribution profiles
Physics of Fluids, 1995Co-Authors: D Kaftori, G Hetsroni, Sanjoy BanerjeeAbstract:The velocity, Flux, and concentration distribution of solid Particles in a turbulent boundary layer of a horizontal water flume were investigated experimentally by means of LDA and visualization techniques. The Particles were of polystyrene (specific density ∼1.05). Results show that coherent wall structures are responsible for most of the characteristics of Particle behavior throughout the boundary layer. Particles are often concentrated in regions of low velocity, associated with wall structures, and as a result the average Particle velocity is lower than the fluid’s. This was also noted previously by Rashidi et al., but not explained. The actual relative velocity between the Particles and the surrounding fluid is often small. In addition, the data suggest that as the shear rate increases, the Particle Flux profiles asymptotically approach a shape where a strong gradient of Particle Flux exists in the lower part of the boundary layer (y+≤250), while it is relatively constant at higher elevations. This phenomenon may also be attributable to interactions with the wall structures.
G Hetsroni - One of the best experts on this subject based on the ideXlab platform.
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Particle behavior in the turbulent boundary layer ii velocity and distribution profiles
Physics of Fluids, 1995Co-Authors: D Kaftori, G Hetsroni, Sanjoy BanerjeeAbstract:The velocity, Flux, and concentration distribution of solid Particles in a turbulent boundary layer of a horizontal water flume were investigated experimentally by means of LDA and visualization techniques. The Particles were of polystyrene (specific density ∼1.05). Results show that coherent wall structures are responsible for most of the characteristics of Particle behavior throughout the boundary layer. Particles are often concentrated in regions of low velocity, associated with wall structures, and as a result the average Particle velocity is lower than the fluid’s. This was also noted previously by Rashidi et al., but not explained. The actual relative velocity between the Particles and the surrounding fluid is often small. In addition, the data suggest that as the shear rate increases, the Particle Flux profiles asymptotically approach a shape where a strong gradient of Particle Flux exists in the lower part of the boundary layer (y+≤250), while it is relatively constant at higher elevations. This p...
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Particle behavior in the turbulent boundary layer ii velocity and distribution profiles
Physics of Fluids, 1995Co-Authors: D Kaftori, G Hetsroni, Sanjoy BanerjeeAbstract:The velocity, Flux, and concentration distribution of solid Particles in a turbulent boundary layer of a horizontal water flume were investigated experimentally by means of LDA and visualization techniques. The Particles were of polystyrene (specific density ∼1.05). Results show that coherent wall structures are responsible for most of the characteristics of Particle behavior throughout the boundary layer. Particles are often concentrated in regions of low velocity, associated with wall structures, and as a result the average Particle velocity is lower than the fluid’s. This was also noted previously by Rashidi et al., but not explained. The actual relative velocity between the Particles and the surrounding fluid is often small. In addition, the data suggest that as the shear rate increases, the Particle Flux profiles asymptotically approach a shape where a strong gradient of Particle Flux exists in the lower part of the boundary layer (y+≤250), while it is relatively constant at higher elevations. This phenomenon may also be attributable to interactions with the wall structures.
Sylvain Pichat - One of the best experts on this subject based on the ideXlab platform.
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modelling the impact of biogenic Particle Flux intensity and composition on sedimentary pa th
Quaternary Science Reviews, 2020Co-Authors: Lise Missiaen, Laurie Menviel, Katrin J Meissner, Didier M Roche, Jean Claude Dutay, Nathaelle Bouttes, Fanny Lhardy, Aurelien Quiquet, Sylvain PichatAbstract:Abstract There is compelling evidence that millennial climate variability of the last glacial period was associated with significant changes in the Atlantic Meridional Overturning Circulation (AMOC). Several North Atlantic sedimentary Pa/Th records indicate a consistent and large Pa/Th increase across millennial-scale events, which has been interpreted as considerable reduction in North Atlantic Deep Water (NADW) formation. However, the use of sedimentary Pa/Th as a pure kinematic circulation proxy is challenging because Pa and Th are also highly sensitive to changes in particulate Flux intensity and composition that might have occurred across these millennial scale events. In this study, we use the Pa/Th enabled iLOVECLIM Earth System Model of intermediate complexity to evaluate the impact of changes in biogenic Particle Flux intensity and composition on the Atlantic Pa/Th. We find that in our model, changes in Particulate Organic Carbon (POC), and to a lesser extent biogenic opal production, can significantly affect the sedimentary Pa/Th, possibly explaining up to 30% of the observed North Atlantic Pa/Th increase across Heinrich stadial 1. The sedimentary Pa/Th response is also likely sensitive to shifts in the geographical distribution of the Particles, especially in high scavenging regions. Our study suggests that a decrease in opal production in the northwest Atlantic can induce a far field Pa/Th increase in a large part of the North Atlantic basin. Therefore, local monitoring of Particle Fluxes may not be sufficient to rule out any influence of changing Particle Fluxes on sedimentary Pa/Th records.
Didier M Roche - One of the best experts on this subject based on the ideXlab platform.
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modelling the impact of biogenic Particle Flux intensity and composition on sedimentary pa th
Quaternary Science Reviews, 2020Co-Authors: Lise Missiaen, Laurie Menviel, Katrin J Meissner, Didier M Roche, Jean Claude Dutay, Nathaelle Bouttes, Fanny Lhardy, Aurelien Quiquet, Sylvain PichatAbstract:Abstract There is compelling evidence that millennial climate variability of the last glacial period was associated with significant changes in the Atlantic Meridional Overturning Circulation (AMOC). Several North Atlantic sedimentary Pa/Th records indicate a consistent and large Pa/Th increase across millennial-scale events, which has been interpreted as considerable reduction in North Atlantic Deep Water (NADW) formation. However, the use of sedimentary Pa/Th as a pure kinematic circulation proxy is challenging because Pa and Th are also highly sensitive to changes in particulate Flux intensity and composition that might have occurred across these millennial scale events. In this study, we use the Pa/Th enabled iLOVECLIM Earth System Model of intermediate complexity to evaluate the impact of changes in biogenic Particle Flux intensity and composition on the Atlantic Pa/Th. We find that in our model, changes in Particulate Organic Carbon (POC), and to a lesser extent biogenic opal production, can significantly affect the sedimentary Pa/Th, possibly explaining up to 30% of the observed North Atlantic Pa/Th increase across Heinrich stadial 1. The sedimentary Pa/Th response is also likely sensitive to shifts in the geographical distribution of the Particles, especially in high scavenging regions. Our study suggests that a decrease in opal production in the northwest Atlantic can induce a far field Pa/Th increase in a large part of the North Atlantic basin. Therefore, local monitoring of Particle Fluxes may not be sufficient to rule out any influence of changing Particle Fluxes on sedimentary Pa/Th records.
