01.2020.105.112

SEAMLESS IMMERSED BOUNDARY METHOD FOR FLOW SIMULATION WITH HEAT TRANSFER ON DUAL-RESOLUTION GRID

Author(s):
K. Tajiri*, M. Tanaka, M. Yamakawa & H. Nishida

Affiliation(s):
Department of Mechanophisics, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan

*Corresponding Author Email: tajiri@kit.ac.jp

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

In this study, we proposed a simulation method combining the dual-resolution grid method and the seamless immersed boundary method (SIBM) for the flow with heat transfer. A finer grid is used than in the flow simulation without heat transfer when applying SIBM to the flow simulation with heat transfer because the grid resolution required by the energy equation is higher than the grid resolution required by the Navier-Stokes equation. In particular, because most of the computational time is generally used to solve the pressure equation in the incompressible flow, solving the pressure equation at the grid resolution required by the energy equation results in a significant loss of computational efficiency. In the present method, the Navier-Stokes equations and energy equations are solved at different resolutions by using the dual-resolution grid in order to perform efficiently the flow simulation with heat transfer. In this study, the present method is applied to the flow around a two-dimensional heated circular cylinder, and the present method is verified by comparing the local Nusselt number on the circular cylinder surface with the result on the single-resolution grid. As a result, the Nusselt number obtained by the present method was close to the Nusselt number by the single-resolution grid with the same grid resolution for the energy equation. Furthermore, in the present method, the computational time was reduced by 60% compared to the single-resolution grid method with the same resolution for the energy equation because the Navier-Stokes equations are solved on a coarser grid than the energy equation. Therefore, it can be said that introducing the dual-resolution grid can greatly reduce the computation time for the flow simulation with heat transfer by using the SIBM. Finally, it is concluded that the present method combining the dual-resolution grid method and SIBM is very promising for the flow simulation with heat transfer involving objects with complicated shapes.