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采用人工模拟实验,对黄土雨滴击溅下坡面薄层漫流的流态、扰动能力和输沙特征进行了研究,结果显示:雨滴击溅作用下坡面薄层漫流的流态既不是层流也不是紊流,属于雨滴垂向作用下的高度混掺“扰动流”;泥沙剥蚀量较无雨滴击溅薄层流剥蚀量显著增大,击溅雨滴直径越大,泥沙剥蚀量也越大,呈指数规律变化,表明雨滴击溅作用是薄层漫流泥沙剥蚀的主要动力。雨滴击溅对薄层漫流的扰动能力随着水流深度和雨滴直径比值的增大呈幂指数关系减小,当雨滴直径大于薄层漫流水深的2.5～3.0倍时,雨滴击溅对薄层漫流基本无扰动作用。基于雨滴击溅的主要影响因子,提出了缓坡坡面扰动系数预测方程,对研究薄层漫流泥沙流失预报模型具有重要意义。
The flow pattern, disturbance capacity and sediment transport characteristics of thin-layer diffusers on the slopes of loess raindrops were studied by artificial simulation. The results show that the laminar flows on the slopes are neither laminar Is not a turbulent flow and belongs to the highly mixed “disturbed flow” under the vertical action of raindrops. The denudation amount of sediment is significantly increased as compared with that of a thin laminar flow without raindrops. The larger the diameter of the raindrops, the denudation of sediment The greater the amount, the exponential change, indicating that the raindrop splashing action is the main driving force of sediment erosion of thin layers. When the raindrop diameter is greater than 2.5 ~ 3.0 times of the depth of the thin layer, the raindrops splash on the thin layer Diffuse basic undisturbed effect. Based on the main influencing factors of raindrop splashing, the prediction equation of slope perturbation coefficient is proposed, which is of great significance for studying the model of predicting runoff loss of thin-bedded sediment.