The Experts below are selected from a list of 9231 Experts worldwide ranked by ideXlab platform
Frédéric Plaza - One of the best experts on this subject based on the ideXlab platform.
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Particle image velocimetry measurements of vortex rings head-on collision with a heated vertical plate
Physics of Fluids, 2010Co-Authors: Gabriel Arévalo, Rodrigo H. Hernández, Christian Nicot, Frédéric PlazaAbstract:We report particle image velocimetry measurements of the collision of a vortex ring with a heated wall kept at constant temperature. We consider the case when both the vortex ring and the thermal boundary layer generated by the vertical heated wall are stable and laminar prior to any interaction. The impingement process can be divided into two parts. (i) A ring-driven stage, where the vortex ring grows in diameter while approaching the wall and therefore it sweeps progressively an increased surface on the wall. (ii) A boundary layer-driven stage, where the vortex ring moves upward due to the thermal convective motion generated by the heated wall. In some cases, the head-on collision triggers the ring’s azimuthal instability as revealed by the formation of vortical structures arranged on a wavy starlike pattern and confirmed by flow visualizations. A single collision generates important velocity gradients and shear stresses along the wall accompanied with the creation of Local Vorticity normal to the verti...
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Particle image velocimetry measurements of vortex rings head-on collision with a heated vertical plate
Physics of Fluids, 2010Co-Authors: Gabriel Arévalo, Rodrigo H. Hernández, Christian Nicot, Frédéric PlazaAbstract:We report particle image velocimetry measurements of the collision of a vortex ring with a heated wall kept at constant temperature. We consider the case when both the vortex ring and the thermal boundary layer generated by the vertical heated wall are stable and laminar prior to any interaction. The impingement process can be divided into two parts. (i) A ring-driven stage, where the vortex ring grows in diameter while approaching the wall and therefore it sweeps progressively an increased surface on the wall. (ii) A boundary layer-driven stage, where the vortex ring moves upward due to the thermal convective motion generated by the heated wall. In some cases, the head-on collision triggers the ring's azimuthal instability as revealed by the formation of vortical structures arranged on a wavy starlike pattern and confirmed by flow visualizations. A single collision generates important velocity gradients and shear stresses along the wall accompanied with the creation of Local Vorticity normal to the vertical heated wall. Peak wall shear stresses occur near the point of impact of the vortex ring core.
Gabriel Arévalo - One of the best experts on this subject based on the ideXlab platform.
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Particle image velocimetry measurements of vortex rings head-on collision with a heated vertical plate
Physics of Fluids, 2010Co-Authors: Gabriel Arévalo, Rodrigo H. Hernández, Christian Nicot, Frédéric PlazaAbstract:We report particle image velocimetry measurements of the collision of a vortex ring with a heated wall kept at constant temperature. We consider the case when both the vortex ring and the thermal boundary layer generated by the vertical heated wall are stable and laminar prior to any interaction. The impingement process can be divided into two parts. (i) A ring-driven stage, where the vortex ring grows in diameter while approaching the wall and therefore it sweeps progressively an increased surface on the wall. (ii) A boundary layer-driven stage, where the vortex ring moves upward due to the thermal convective motion generated by the heated wall. In some cases, the head-on collision triggers the ring’s azimuthal instability as revealed by the formation of vortical structures arranged on a wavy starlike pattern and confirmed by flow visualizations. A single collision generates important velocity gradients and shear stresses along the wall accompanied with the creation of Local Vorticity normal to the verti...
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Particle image velocimetry measurements of vortex rings head-on collision with a heated vertical plate
Physics of Fluids, 2010Co-Authors: Gabriel Arévalo, Rodrigo H. Hernández, Christian Nicot, Frédéric PlazaAbstract:We report particle image velocimetry measurements of the collision of a vortex ring with a heated wall kept at constant temperature. We consider the case when both the vortex ring and the thermal boundary layer generated by the vertical heated wall are stable and laminar prior to any interaction. The impingement process can be divided into two parts. (i) A ring-driven stage, where the vortex ring grows in diameter while approaching the wall and therefore it sweeps progressively an increased surface on the wall. (ii) A boundary layer-driven stage, where the vortex ring moves upward due to the thermal convective motion generated by the heated wall. In some cases, the head-on collision triggers the ring's azimuthal instability as revealed by the formation of vortical structures arranged on a wavy starlike pattern and confirmed by flow visualizations. A single collision generates important velocity gradients and shear stresses along the wall accompanied with the creation of Local Vorticity normal to the vertical heated wall. Peak wall shear stresses occur near the point of impact of the vortex ring core.
Rodrigo H. Hernández - One of the best experts on this subject based on the ideXlab platform.
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Particle image velocimetry measurements of vortex rings head-on collision with a heated vertical plate
Physics of Fluids, 2010Co-Authors: Gabriel Arévalo, Rodrigo H. Hernández, Christian Nicot, Frédéric PlazaAbstract:We report particle image velocimetry measurements of the collision of a vortex ring with a heated wall kept at constant temperature. We consider the case when both the vortex ring and the thermal boundary layer generated by the vertical heated wall are stable and laminar prior to any interaction. The impingement process can be divided into two parts. (i) A ring-driven stage, where the vortex ring grows in diameter while approaching the wall and therefore it sweeps progressively an increased surface on the wall. (ii) A boundary layer-driven stage, where the vortex ring moves upward due to the thermal convective motion generated by the heated wall. In some cases, the head-on collision triggers the ring’s azimuthal instability as revealed by the formation of vortical structures arranged on a wavy starlike pattern and confirmed by flow visualizations. A single collision generates important velocity gradients and shear stresses along the wall accompanied with the creation of Local Vorticity normal to the verti...
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Particle image velocimetry measurements of vortex rings head-on collision with a heated vertical plate
Physics of Fluids, 2010Co-Authors: Gabriel Arévalo, Rodrigo H. Hernández, Christian Nicot, Frédéric PlazaAbstract:We report particle image velocimetry measurements of the collision of a vortex ring with a heated wall kept at constant temperature. We consider the case when both the vortex ring and the thermal boundary layer generated by the vertical heated wall are stable and laminar prior to any interaction. The impingement process can be divided into two parts. (i) A ring-driven stage, where the vortex ring grows in diameter while approaching the wall and therefore it sweeps progressively an increased surface on the wall. (ii) A boundary layer-driven stage, where the vortex ring moves upward due to the thermal convective motion generated by the heated wall. In some cases, the head-on collision triggers the ring's azimuthal instability as revealed by the formation of vortical structures arranged on a wavy starlike pattern and confirmed by flow visualizations. A single collision generates important velocity gradients and shear stresses along the wall accompanied with the creation of Local Vorticity normal to the vertical heated wall. Peak wall shear stresses occur near the point of impact of the vortex ring core.
Christian Nicot - One of the best experts on this subject based on the ideXlab platform.
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Particle image velocimetry measurements of vortex rings head-on collision with a heated vertical plate
Physics of Fluids, 2010Co-Authors: Gabriel Arévalo, Rodrigo H. Hernández, Christian Nicot, Frédéric PlazaAbstract:We report particle image velocimetry measurements of the collision of a vortex ring with a heated wall kept at constant temperature. We consider the case when both the vortex ring and the thermal boundary layer generated by the vertical heated wall are stable and laminar prior to any interaction. The impingement process can be divided into two parts. (i) A ring-driven stage, where the vortex ring grows in diameter while approaching the wall and therefore it sweeps progressively an increased surface on the wall. (ii) A boundary layer-driven stage, where the vortex ring moves upward due to the thermal convective motion generated by the heated wall. In some cases, the head-on collision triggers the ring’s azimuthal instability as revealed by the formation of vortical structures arranged on a wavy starlike pattern and confirmed by flow visualizations. A single collision generates important velocity gradients and shear stresses along the wall accompanied with the creation of Local Vorticity normal to the verti...
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Particle image velocimetry measurements of vortex rings head-on collision with a heated vertical plate
Physics of Fluids, 2010Co-Authors: Gabriel Arévalo, Rodrigo H. Hernández, Christian Nicot, Frédéric PlazaAbstract:We report particle image velocimetry measurements of the collision of a vortex ring with a heated wall kept at constant temperature. We consider the case when both the vortex ring and the thermal boundary layer generated by the vertical heated wall are stable and laminar prior to any interaction. The impingement process can be divided into two parts. (i) A ring-driven stage, where the vortex ring grows in diameter while approaching the wall and therefore it sweeps progressively an increased surface on the wall. (ii) A boundary layer-driven stage, where the vortex ring moves upward due to the thermal convective motion generated by the heated wall. In some cases, the head-on collision triggers the ring's azimuthal instability as revealed by the formation of vortical structures arranged on a wavy starlike pattern and confirmed by flow visualizations. A single collision generates important velocity gradients and shear stresses along the wall accompanied with the creation of Local Vorticity normal to the vertical heated wall. Peak wall shear stresses occur near the point of impact of the vortex ring core.
Ronald E. Rosensweig - One of the best experts on this subject based on the ideXlab platform.
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Assembly of microscopic highly magnetic droplets: Magnetic alignment versus viscous drag
Physical Review E, 1999Co-Authors: Olivier Sandre, Régine Perzynski, Julien Browaeys, Jean-claude Bacri, Valérie Cabuil, Ronald E. RosensweigAbstract:We report here the collective behavior of droplets in the scale 10−6–10−5m made of a concentrated magnetic fluid elongated and oriented by a magnetic field while rotating synchronously with respect to the carrier liquid. Distribution of droplet sizes is studied as a function of a magnetoviscous number Nmv that quantifies the competition between magnetic field and Local Vorticity. The liquid state and very low interfacial tension enable both breakup and coalescence processes, which are undergone by the droplet population to reach dynamic equilibrium. Theoretical analysis of a single drop motion is extended to the case of the drop assembly. Experiments combining rotation and field modulation show a regime of nonsteady rotation in good agreement with theory.
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Assembly of microscopic highly magnetic droplets: Magnetic alignment versus viscous drag
Physical Review E, 1999Co-Authors: Olivier Sandre, Régine Perzynski, Julien Browaeys, Jean-claude Bacri, Valérie Cabuil, Ronald E. RosensweigAbstract:We report here the collective behavior of droplets in the scale ${10}^{\ensuremath{-}6}--{10}^{\ensuremath{-}5}\mathrm{m}$ made of a concentrated magnetic fluid elongated and oriented by a magnetic field while rotating synchronously with respect to the carrier liquid. Distribution of droplet sizes is studied as a function of a magnetoviscous number ${N}_{\mathrm{mv}}$ that quantifies the competition between magnetic field and Local Vorticity. The liquid state and very low interfacial tension enable both breakup and coalescence processes, which are undergone by the droplet population to reach dynamic equilibrium. Theoretical analysis of a single drop motion is extended to the case of the drop assembly. Experiments combining rotation and field modulation show a regime of nonsteady rotation in good agreement with theory.
