Solving Preconditioned Euler/Navier-Stokes Equations for Numerical Simulation of Cavitating Flows Using a Barotropic Model

Ezzatneshan, Eslam | 2008

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 40134 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Hejranfar, Kazem
  7. Abstract:
  8. Cavitation can occur in many fluid systems such as pumps, nozzles, hydrofoils and submarine vehicles and therefore, numerical modeling of this phenomenon has a significant importance. In this study, the numerical simulation of the cavitating flows through the Euler/Navier-Stokes equations employing the interface capturing method associated with a barotropic state law is performed. The system of governing equations is discretized using a cell-centered finite-volume algorithm and the fluxes are evaluated using a central-difference scheme. To account for density jumps across the cavity interface, the numerical dissipation terms with suitable density and pressure sensors are used. Since cavitating flows are largely incompressible except in the vicinity of the interface region, the order of magnitude of the eigenvalues is different which makes the system of equations to be stiff. A preconditioning procedure is implemented to reduce the stiffness of the system of equations and to improve the performance of the algorithm in modeling cavitating flows. A sensitivity study is conducted to evaluate the effects of various parameters such as numerical dissipation coefficients and preconditioning on the accuracy and performance of the solution. Numerical simulations of inviscid, laminar and turbulent cavitating flows over two hydrofoils and a hemispherical headform for different conditions are carried out. For turbulence flow computations, the algebraic Baldwin-Lomax (BL) model and a combination of the Baldwin-Lomax and Smagorinsky (BLS) models are used. The results are compared with the available numerical and experimental results
  9. Keywords:
  10. Numerical Simulation ; Precondition Algorithm ; Barotropic Flow ; Cavitation Flow ; Navier-Stokes Equation

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