溃坝水流作用下急弯河道泥沙输移数值模拟

摘要

Finite element characteristics split ( CBS) algorithm was used to solve the equation of two dimensional shallow flow and a mathematical model for simulating the sediment transport under dam-break flow was established. CBS algorithm has good stability and accuracy in solving convection dominated problems, which can be applied to dam break flow that is characterized as large velocity, rapid change of water level and river bed. The validity of the model was verified by comparison of the calculated result with the experiment data of a full dam break flow in 90° sharp flume. On this basis, the model was further used to calculate flood routing and sediment transport under dam break flow field in 180° sharp bend at gentle slope and steep slope respectively. The results show that the model can simulate the dam break flow movement, and the results comply with the laws of flow and sedi-ment movement.%将有限元特征分裂算法( CBS)应用于二维浅水控制方程的求解中，建立了模拟溃坝水流泥沙输移的数学模型。 CBS算法在计算对流主导的问题时具有很好的稳定性与较高的精度，适用于处理溃坝水流流速大，水位、床面变化剧烈等问题。应用该模型对90°急弯河道全溃所致的水流运动进行了数值计算，并与试验资料进行了比较，证实了该方法的可靠性。最后用该模型模拟了180°弯道中溃坝水流在缓坡、陡坡时的洪水演进与泥沙输移。结果表明：模型能够较好地模拟溃坝水流运动，模拟结果符合水流泥沙运动规律。