基于雷诺平均的水沙两相流方程,建立了一个非平衡全沙输移二维数学模型.模型考虑相间相对运动以及多颗粒之间的相互影响,通过相间作用力进行两相耦合.和传统的单相流模型以及低浓度两相流模型相比,该模型摆脱了依赖经验公式给定床面边界条件的局限性.针对明渠净冲刷问题,在合理给定水相和泥沙相边界条件的前提下计算了泥沙浓度分布的沿程变化,并利用物理模型实验的结果和理论解验证了数学模型的正确性,同时也分析了明渠净冲刷问题中紊动扩散和重力沉降现象的特征.%A numerical model for non-equilibrium sediment transport is developed based on Reynolds averaged two-phase flow equations.Different from most of the previous models,the present one does not require an empirical formula to deal with the pick-up and settling of sediment over the bed.The model includes the interactions between particles,and between fluid and particles.The two-phases are coupled through the interphase forces.The model is employed to predict the longitudinal variation of the sediment concentration profile over an eroding bed under a steady uniform flow.Computational results agree reasonably well with the available experimental data and are evidently more accurate than the analytical solution.The relevant turbulent diffusion and gravity settling are also discussed.
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