운동하는 물체 주위 비압축성 열유동 해석을 위한 무격자법 기반의 시뮬레이션 기술 개발

Abstract

When performing CFD(Computational Fluid Dynamics) simulations, solvers and schemes with discretizing governing equations by FVM(Finite Volume Method) and adopting unstructured grids are generally used because of its advantage over the conventional approach using structured grid. However, the grid generation process can still be very time consuming and needs toughness for a complex geometry. Moreover, the convergence and accuracy of the simulation results are very much affected by the quality of the grid. On the contrary, the gridless (or meshfree) methods are feasible and robust for the problems with moving boundary and/or complicated boundary shapes, because these methods do not need to generate a grid system. In this study, a newly-developed Eulerian gridless solver for the simulation of two-dimensional unsteady incompressible viscous thermal flows around a moving body in the low Reynolds number is introduced. The convection and diffusion equation of heat with adopting Boussinesq approximation is added to deal with heat transfer phenomena. For the implementation of a moving body, moving domain method based on ALE(Arbitrary Lagrangian Eulerian) technique is adopted. The spatial derivatives of governing equations are solved by WMLS(Weighted Moving Least Square) interpolations on a cloud of points. A Fractional time step method is adopted and the Poission equation for the pressure are solved by successively in the WMLS sense. Some benchmark simulations of the flows including heat transfer and a moving body are solved by the developed solver for the validation and the results are compared with analytic solution and those by experiments and other CFD simulations.