为阐明水库冲刷漏斗的形成机理，开展坝区泥沙淤积的三维数值模拟研究。三维水沙数学模型使用平面非结构、垂向sigma网格和θ半隐、欧拉‐拉格朗日追踪等数值方法，具有良好的复杂边界适应能力和计算稳定性。根据一、三维数学模型对比计算分析，确定三维数学模型的参数；在此基础上，采用三维数学模型模拟完整的水库坝区泥沙淤积过程。模拟Karot水库坝区20 a的泥沙输移与淤积过程，得到了坝区水沙因子和河床冲於分布。结果表明：水库中泥沙主要沿着主流通道输运和淤积，与此同时，在该通道两侧、出流孔前平面环流的作用下折射挟沙水流形成集中淤积；随着水库运行年限增加，库区的高滩深槽逐步向水库出口推进，在坝区两侧集中淤积体之间、出流孔口前逐渐形成冲刷漏斗。%To illuminate the development mechanics of a reservoir scouring funnel ,the sediment deposition before a dam was simulated using a 3D numerical model .The 3D model used an unstructured ,sigma grid , which fitted well complex boundaries of real rivers . The θsemi‐implicit method ,Eulerian‐Lagrangian method w ere combined to discretize the governing equations , w hich made the computation stable . T he parameters of the 3D model were determined by comparing the simulated results of the 1D and 3D models . The sedimentation process before the orifices of a reservoir was then simulated by the 3D model with calibrated parameters . T he process of 20‐year sediment transport and deposition before the dam of the Pakistan Karot reservoir was simulated ,and the distributions of the flows ,sediment concentration and deposition were obtained .The results indicate that :(1) in a reservoir ,the sediment is transported and deposits in the main channel ,at two sides of which intensive depositions of refraction sediment‐carrying flows occur along the horizontal circulation before orifices ;(2) with the aging of the reservoir ,the high floodplain and deep channel are gradually advanced towards the orifices ,the scouring funnel is then formed between the above intensive depositions and before the orifices .
展开▼
