Tsunakiyo Iribe

REDUCTION OF COMMUNICATION IN PARALLEL COMPUTING OF PARTICLE METHOD FOR FLOW SIMULATION OF SEASIDE AREAS

Methods for reduction in communication time during parallel computation of a particle method for flow simulation of seaside areas are presented. Since the analysis region was divided for parallel computation using a PC cluster, communications among processors were necessary. Two techniques were tested. The first was renumbering, which reduced the amount of communication. The second was the use of a communication list including the maximum and minimum particle numbers. These techniques improved communication speed. Performance during large-scale simulation was examined by computing tsunami wave run-up on a seaside area using 6,300,000 particles. A calculation time of 237 hr was used to generate real time data for 60s.

Coupled effects of Coastal dune and forest against Tsunami

After the 3.11-Tsunami in the Tohoku Region of Japan in 2011, many comprehensive field observations on tsunami damages were done. The coastline areas of Tohoku had coastal dunes and forests could have acted as a barrier against the tsunami. But surveys have shown that almost all of the coastal forest was swept away with its roots by the tsunami, and houses behind these forests were not spared and were completely destroyed and washed way. However, some houses and manmade structures were able to withstand the strength of the tsunami waves. These houses were located behind both coastal dunes and forests, which efficiently acted as a barrier against the tsunami. In this paper, the effects of the dunes and the forest on tsunami currents are studied through hydraulic experiments, and the coupled effect of the dunes and forests as coastal barriers are also studied.