各種水域の乱流構造特性とその移動床問題への水工学的応用に関する研究

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In this study we clarify the fundamental characteristics of the non-equilibrium sediment transport, paying attention to the interaction between the motion of sand particles and turbulent structures under the various kinds of flow fields. One of the typical phenomena of the sediment transport is transient process, which can be described by the stochastic model. We proposed the widely applicable stochastic model to the non-equilibrium fluvial process under the unsteady and non-uniform flow fields. That model consists of the pick-up rate, step length and moving period. Next, the flow structures are experimentally and theoretically investigated under the various kind boundary conditions, i. e. unsteady open channel flow, oscillation-current coexisting flow, flow with vegetated area, flow over the gravel bed and so on. The characteristics of the sediment transport mechanism are, examined@ by associating the deterministic solution of sand particle to the irregularities of the flow and boundary conditions. The key point is the harmony between the deterministic approach and the stodhastic approach.The proposed model shows the good agreement with the various kinds of the experimental data, and its appicability is recognized.