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Hydrodynamique instationnaire d'un cylindre sous choc

Abstract : A theoretical, numerical and experimental approaches are developed to study the transient hydrodynamics of a cylinder under shock conditions. The theoretical approach consists of the construction of a general model for the prediction of the force and pressure distribution around the cylinder for any transient motions in a viscous two-dimensional fluid domain. The numerical modeling is based on a moving meshing of the fluid domain using the CFD code, STAR-CD. An experimental set-up has been built that is able to generate different motion profiles (sinusoidal acceleration, harmonic motion) for a cylinder in a tank. These three complementary approaches have shown the induced flow is governed by two non-dimensional numbers : the Stokes number, Beta, and the Keulegan-Carpenter number, KC. Beta is a measure of the ratio between the viscous and the shock time scales and KC is the ratio between the maximum displacement of the cylinder and its diameter. When Beta is high (inviscid flow), the force on the cylinder is dominated by the inertial effect for any KC. At low KC, the pressure is monitored only by inertial effect whereas, for high KC, an advection effect is added. At moderate beta and for low value of KC, three effects act on the force and pressure : the inertial, the history and the drag effects. For high value of KC, the flow becomes more complex : vortical flow structures appear. These latter induce strong local pressure fluctuations without modifying the global force. The last part of this work is a study of a fluid-structure interaction problem. Theoretical analysis and numerical code are employed to treat this problem. Inertial, history and drag effects appears simultaneously and are coupled with the cylinder motion.
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https://tel.archives-ouvertes.fr/tel-00124063
Contributor : Vincent Melot <>
Submitted on : Friday, January 12, 2007 - 11:19:35 AM
Last modification on : Tuesday, July 2, 2019 - 3:04:41 PM
Long-term archiving on: : Tuesday, April 6, 2010 - 8:55:42 PM

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  • HAL Id : tel-00124063, version 1

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Vincent Melot. Hydrodynamique instationnaire d'un cylindre sous choc. Dynamique des Fluides [physics.flu-dyn]. Université de Nantes, 2006. Français. ⟨tel-00124063⟩

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