The Experts below are selected from a list of 1668 Experts worldwide ranked by ideXlab platform
Patrick Marsaleix - One of the best experts on this subject based on the ideXlab platform.
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Seasonal and Tidal variability of the hydrology and suspended particulate matter in the Van Uc estuary, Red River, Vietnam
Journal of Marine Systems, 2020Co-Authors: Violaine Piton, Sylvain Ouillon, Vu Duy Vinh, Gael Many, Marine Herrmann, Patrick MarsaleixAbstract:This study explores the seasonal and Tidal changes in flow and suspended matter dynamics in the tropical and macroTidal Van Uc River estuary (North Vietnam) and aims at understanding, among others, the sediment delivery to the ocean and the processes behind the estuary siltation. Four campaigns took place during the contrasting high flow and low flow seasons, for each during neap and spring tides. Water and suspended matter fluxes, salinity, turbidity and suspended sediment concentrations were measured for 24h at three cross sections along the estuary. During the high-flow season, the estuary was mixed, with seaward sediment flux during neap tide and ephemeral up-estuary sediment flux at spring tides due to Tidal Distortion. During the low-flow season, the system transitioned from partially mixed to highly stratified with salty waters intrusions, salt wedge presence and up-estuary sediment flux varying with the Tidal regime. Estuarine siltation mostly occurred during low-flow at spring tides with a suspended matter inflow, primarily due to local resuspension, which represented ⅔ of the outflow. These findings also provide a new benchmark for hydro-sedimentary model calibration/validation.
Violaine Piton - One of the best experts on this subject based on the ideXlab platform.
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Seasonal and Tidal variability of the hydrology and suspended particulate matter in the Van Uc estuary, Red River, Vietnam
Journal of Marine Systems, 2020Co-Authors: Violaine Piton, Sylvain Ouillon, Vu Duy Vinh, Gael Many, Marine Herrmann, Patrick MarsaleixAbstract:This study explores the seasonal and Tidal changes in flow and suspended matter dynamics in the tropical and macroTidal Van Uc River estuary (North Vietnam) and aims at understanding, among others, the sediment delivery to the ocean and the processes behind the estuary siltation. Four campaigns took place during the contrasting high flow and low flow seasons, for each during neap and spring tides. Water and suspended matter fluxes, salinity, turbidity and suspended sediment concentrations were measured for 24h at three cross sections along the estuary. During the high-flow season, the estuary was mixed, with seaward sediment flux during neap tide and ephemeral up-estuary sediment flux at spring tides due to Tidal Distortion. During the low-flow season, the system transitioned from partially mixed to highly stratified with salty waters intrusions, salt wedge presence and up-estuary sediment flux varying with the Tidal regime. Estuarine siltation mostly occurred during low-flow at spring tides with a suspended matter inflow, primarily due to local resuspension, which represented ⅔ of the outflow. These findings also provide a new benchmark for hydro-sedimentary model calibration/validation.
Stephen O'sullivan - One of the best experts on this subject based on the ideXlab platform.
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Strong-field Tidal Distortions of rotating black holes. III. Embeddings in hyperbolic three-space
Physical Review D, 2017Co-Authors: Robert F. Penna, Scott A. Hughes, Stephen O'sullivanAbstract:In previous work, we developed tools for quantifying the Tidal Distortion of a black hole's event horizon due to an orbiting companion. These tools use techniques which require large mass ratios (companion mass $\mu$ much smaller than black hole mass $M$), but can be used for arbitrary bound orbits, and for any black hole spin. We also showed how to visualize these distorted black holes by embedding their horizons in a global Euclidean 3-space, ${\mathbb{E}}^3$. Such visualizations illustrate interesting and important information about horizon dynamics. Unfortunately, we could not visualize black holes with spin parameter $a_* > \sqrt{3}/2 \approx 0.866$: such holes cannot be globally embedded into ${\mathbb{E}}^3$. In this paper, we overcome this difficulty by showing how to embed the horizons of Tidally distorted Kerr black holes in a hyperbolic 3-space, ${\mathbb{H}}^3$. We use black hole perturbation theory to compute the Gaussian curvatures of Tidally distorted event horizons, from which we build a two-dimensional metric of their distorted horizons. We develop a numerical method for embedding the Tidally distorted horizons in ${\mathbb{H}}^3$. As an application, we give a sequence of embeddings into ${\mathbb{H}}^3$ of a Tidally interacting black hole with spin $a_*=0.9999$. A small amplitude, high frequency oscillation seen in previous work shows up particularly clearly in these embeddings.
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Strong-field Tidal Distortions of rotating black holes: Formalism and results for circular, equatorial orbits
Physical Review D, 2014Co-Authors: Stephen O'sullivan, Scott A. HughesAbstract:Tidal coupling between members of a compact binary system can have an interesting and important influence on that binary's dynamical inspiral. Tidal coupling also distorts the binary's members, changing them (at lowest order) from spheres to ellipsoids. At least in the limit of fluid bodies and Newtonian gravity, there are simple connections between the geometry of the distorted ellipsoid and the impact of tides on the orbit's evolution. In this paper, we develop tools for investigating Tidal Distortions of rapidly rotating black holes using techniques that are good for strong-field, fast-motion binary orbits. We use black hole perturbation theory, so our results assume extreme mass ratios. We develop tools to compute the Distortion to a black hole's curvature for any spin parameter, and for Tidal fields arising from any bound orbit, in the frequency domain. We also develop tools to visualize the horizon's Distortion for black hole spin $a/M \le \sqrt{3}/2$ (leaving the more complicated $a/M > \sqrt{3}/2$ case to a future analysis). We then study how a Kerr black hole's event horizon is distorted by a small body in a circular, equatorial orbit. We find that the connection between the geometry of Tidal Distortion and the orbit's evolution is not as simple as in the Newtonian limit.
Scott A. Hughes - One of the best experts on this subject based on the ideXlab platform.
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Strong-field Tidal Distortions of rotating black holes. III. Embeddings in hyperbolic three-space
Physical Review D, 2017Co-Authors: Robert F. Penna, Scott A. Hughes, Stephen O'sullivanAbstract:In previous work, we developed tools for quantifying the Tidal Distortion of a black hole's event horizon due to an orbiting companion. These tools use techniques which require large mass ratios (companion mass $\mu$ much smaller than black hole mass $M$), but can be used for arbitrary bound orbits, and for any black hole spin. We also showed how to visualize these distorted black holes by embedding their horizons in a global Euclidean 3-space, ${\mathbb{E}}^3$. Such visualizations illustrate interesting and important information about horizon dynamics. Unfortunately, we could not visualize black holes with spin parameter $a_* > \sqrt{3}/2 \approx 0.866$: such holes cannot be globally embedded into ${\mathbb{E}}^3$. In this paper, we overcome this difficulty by showing how to embed the horizons of Tidally distorted Kerr black holes in a hyperbolic 3-space, ${\mathbb{H}}^3$. We use black hole perturbation theory to compute the Gaussian curvatures of Tidally distorted event horizons, from which we build a two-dimensional metric of their distorted horizons. We develop a numerical method for embedding the Tidally distorted horizons in ${\mathbb{H}}^3$. As an application, we give a sequence of embeddings into ${\mathbb{H}}^3$ of a Tidally interacting black hole with spin $a_*=0.9999$. A small amplitude, high frequency oscillation seen in previous work shows up particularly clearly in these embeddings.
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Strong-field Tidal Distortions of rotating black holes: Formalism and results for circular, equatorial orbits
Physical Review D, 2014Co-Authors: Stephen O'sullivan, Scott A. HughesAbstract:Tidal coupling between members of a compact binary system can have an interesting and important influence on that binary's dynamical inspiral. Tidal coupling also distorts the binary's members, changing them (at lowest order) from spheres to ellipsoids. At least in the limit of fluid bodies and Newtonian gravity, there are simple connections between the geometry of the distorted ellipsoid and the impact of tides on the orbit's evolution. In this paper, we develop tools for investigating Tidal Distortions of rapidly rotating black holes using techniques that are good for strong-field, fast-motion binary orbits. We use black hole perturbation theory, so our results assume extreme mass ratios. We develop tools to compute the Distortion to a black hole's curvature for any spin parameter, and for Tidal fields arising from any bound orbit, in the frequency domain. We also develop tools to visualize the horizon's Distortion for black hole spin $a/M \le \sqrt{3}/2$ (leaving the more complicated $a/M > \sqrt{3}/2$ case to a future analysis). We then study how a Kerr black hole's event horizon is distorted by a small body in a circular, equatorial orbit. We find that the connection between the geometry of Tidal Distortion and the orbit's evolution is not as simple as in the Newtonian limit.
Gael Many - One of the best experts on this subject based on the ideXlab platform.
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Seasonal and Tidal variability of the hydrology and suspended particulate matter in the Van Uc estuary, Red River, Vietnam
Journal of Marine Systems, 2020Co-Authors: Violaine Piton, Sylvain Ouillon, Vu Duy Vinh, Gael Many, Marine Herrmann, Patrick MarsaleixAbstract:This study explores the seasonal and Tidal changes in flow and suspended matter dynamics in the tropical and macroTidal Van Uc River estuary (North Vietnam) and aims at understanding, among others, the sediment delivery to the ocean and the processes behind the estuary siltation. Four campaigns took place during the contrasting high flow and low flow seasons, for each during neap and spring tides. Water and suspended matter fluxes, salinity, turbidity and suspended sediment concentrations were measured for 24h at three cross sections along the estuary. During the high-flow season, the estuary was mixed, with seaward sediment flux during neap tide and ephemeral up-estuary sediment flux at spring tides due to Tidal Distortion. During the low-flow season, the system transitioned from partially mixed to highly stratified with salty waters intrusions, salt wedge presence and up-estuary sediment flux varying with the Tidal regime. Estuarine siltation mostly occurred during low-flow at spring tides with a suspended matter inflow, primarily due to local resuspension, which represented ⅔ of the outflow. These findings also provide a new benchmark for hydro-sedimentary model calibration/validation.