In this paper, two novel numerical computation methods are introduced which have been recently developed at Research Institute for Applied Mechanics （ R/AM ）, Kyushu University, for strongly nonlinear wave-body inte...In this paper, two novel numerical computation methods are introduced which have been recently developed at Research Institute for Applied Mechanics （ R/AM ）, Kyushu University, for strongly nonlinear wave-body interaction problems, such as ship motions in rough seas and resulting green-water impact on deck. The first method is the CIP-based Cartesian grid method, in which the free surface flow is treated as a multi-phase flow which is solved using a Cartesian grid. The second method is the MPS method, which is a so-called particle method and hence no grid is used. The features and calculation procedures of these numerical methods are described. One validation computation against a newly conducted experiment on a dam break problem, which is also described in this paper, is presented.展开更多
This paper presents new experimental data of the erosion rate and sediment transport rate during the processes of dam break caused by overtopping. In order to study the headcut migration, the erosion coefficient was c...This paper presents new experimental data of the erosion rate and sediment transport rate during the processes of dam break caused by overtopping. In order to study the headcut migration, the erosion coefficient was calculated and its peak value was determined near the downstream edge of the dam crest. Then the characteristics of vertical erosion during dam break processes were analyzed by dividing the dam into three regions： the upstream region, middle region, and downstream region. The three regions show different features during headcut migration, but all are exposed to the most intense erosion at the third stage of the dam break process. Finally, three relevant parameters affecting sediment transport were discussed： the length of the dam crest, the inner slope, and the dam composition. The results show that a longer dam crest and flatter inner slope reduce the peak sediment transport rate and prolong the arrival time of peak sediment transport rate; and with the increase of the non-uniformity coefficient S, the peak sediment transport rate initially increases, and then decreases.展开更多
文摘In this paper, two novel numerical computation methods are introduced which have been recently developed at Research Institute for Applied Mechanics （ R/AM ）, Kyushu University, for strongly nonlinear wave-body interaction problems, such as ship motions in rough seas and resulting green-water impact on deck. The first method is the CIP-based Cartesian grid method, in which the free surface flow is treated as a multi-phase flow which is solved using a Cartesian grid. The second method is the MPS method, which is a so-called particle method and hence no grid is used. The features and calculation procedures of these numerical methods are described. One validation computation against a newly conducted experiment on a dam break problem, which is also described in this paper, is presented.
基金supported by the National Natural Science Foundation of China(Grants No50979064 and 51079090)
文摘This paper presents new experimental data of the erosion rate and sediment transport rate during the processes of dam break caused by overtopping. In order to study the headcut migration, the erosion coefficient was calculated and its peak value was determined near the downstream edge of the dam crest. Then the characteristics of vertical erosion during dam break processes were analyzed by dividing the dam into three regions： the upstream region, middle region, and downstream region. The three regions show different features during headcut migration, but all are exposed to the most intense erosion at the third stage of the dam break process. Finally, three relevant parameters affecting sediment transport were discussed： the length of the dam crest, the inner slope, and the dam composition. The results show that a longer dam crest and flatter inner slope reduce the peak sediment transport rate and prolong the arrival time of peak sediment transport rate; and with the increase of the non-uniformity coefficient S, the peak sediment transport rate initially increases, and then decreases.
