غلامرضا ایمانی

In this study, a ghost fluid-lattice Boltzmann method is developed to simulate the conjugate heat transfer at solid-fluid moving curved boundaries. At first,fundamentals of hydrodynamic and thermal lattice Boltzmann method and also methods of imposing curved boundaries in previous studies, are explained. Then using ghost fluid approach, a numerical algorithm for both Neumann and Dirichlet curved boundary conditions has been developed. This algorithm is also developed for solid-fluid conjugate curved boundaries. To the best knowledge of the authors, this is the only method to simulate all of these three boundary conditions with a similar approach. To examine the accuracy of the presented methods, at first the basic numerical code has been tested in several geometries without curved boundaries,then through simulating fluid flow and heat transfer in curved boundary geometries, the accuracy of presented methods for Dirichlet, Neumann, and conjugate boundary conditions has been investigated. Results show that the proposed method possesses the second order accuracy in simulating all of these boundary conditions. Even in calculating heat flux on conjugate curved interfaces, this method, unlike previous methods, has second order convergence. After that, refilling method is developed and combined with ghost fluid method to impose moving curved boundaries. To demonstrate the accuracy of this method, using Galilean invariance concept, several geometries with similar relative velocities and different velocities at origin of coordinates are simulated. According to Galilean invariance principle, these geometries are completely similar, so by comparing the simulation results of these geometries, the accuracy of present method for moving curved boundaries is proved. Then for more investigation of this method, particle suspension in fluid is simulated with different geometries and the results have been compared with those of other studies to investigate the accuracy of present metho