Author(s)

T. Watanabe, K. Kono & H. Ohashi

Abstract

Parallel simulation programs using the lattice fluid methods are developed for studying the transport phenomena in porous media. The domain decomposition technique is applied and the message passing interface library is used for parallelization. Sample problems are solved to validate the simulation programs and evaluate parallel efficiency. It is shown for the LBGK simulations, in which the amount of data transfer between two processors is constant, that the on-node- parallel calculation using shared memory is effective for the calculation time and the memory usage in comparison with the purely distributed calculations. The efficiency of data transfer for the RLG simulations, in which the amount of data transfer varies every time step, is found to be better for sending the number of data and some amount of particle data at the same time. 1 Introduction It is of importance for safety assessment of geological disposal of high-level radioactive waste (HLW) to predict the transport phenomena in the natural barrier such as rock matrix. Numerical simulations of those phenomena are extremely difficult since the material transport mechanism of HLW is complicated due to geometrical complexity of rock matrix and multiple physical and chemical phenomena in groundwater. A joint research project is being carried out by University of Tokyo, Fuji Research Institute and Japan Atomic Energy Research Institute to establish a simulation system for geological disposal of HLW. The project consists of a development of a multi-scale simulation method using lattice fluid models and a

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