Simulation of Behavior of a Single Cavitating Bubble Near Solid Boundariesby solvingTwophase Navier-Stokes Equations with a Central Difference Finite Volume Method

Mortezazadeh Dorostkar, Mohammad | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 46063 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Enginnering
  6. Advisor(s): Hejranfar, Kazem
  7. Abstract:
  8. In the present work, the deformation and collapse of a single cavitating bubble near solid boundaries is simulated by solving the preconditioned, homogenous, multiphaseNavier-Stokes equations. Up to now, all studies in the literature performed by the volume of fluid (VOF)approach to capture the bubble surface have been based on the pressure-based category in which the flow variables are calculated through solving the Poisson equation. Here, the density-based category is applied and the solution methodology is based on the artificial compressibility approach. The compressible form of the Navier-Stokes equations is applied inside the bubble and the liquid phase is assumed to be incompressible. The system of governing equations is discretized by using a central difference finite volume scheme. The flow variables such as the density and the pressure have a sharp jump across the interface and thus an appropriate stabilization procedure should be implemented. In this study, to account for density and pressure jumps across the interface, the numerical dissipation terms with appropriate density and pressure sensors are utilized. The surface tension is considered as a source term in the Navier-Stokes equations and the continuum surface force (CSF) model is applied to account for the surface tension effect. Different test cases, namely, the Couette flow, the Rayleigh-Taylor problem, the dam breakingand the deformation of oval bubble are simulated for the validation of the present solution algorithm. Finally, the deformation and collapse of a single cavitating bubble near two parallel walls for different initial inside to outside pressure ratios of the bubble are simulated and the results obtained discussed
  9. Keywords:
  10. Alveolar Collapses ; Volume of Fluid ; Central Difference Finite Volume Method ; Cavitation Bubble ; Solid Wall

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