挟沙射流是一种以射流为主要载体的水沙二相运动，它在自然界和工程领域中广泛存在。本项目以污水深海排放过程中所形成的低浓度挟沙射流为主要研究对象，采用物理实验和数值模拟相结合的方法，重点研究波流环境下挟沙射流中泥沙的输运和沉降规律，分析波流环境下挟沙射流中泥沙的运动形态及其分区特性，描述波流环境下挟沙射流中泥沙浓度的时空分布特征，建立波流环境下挟沙射流中底部泥沙沉积速率的计算方法。预期可以系统揭示波流环境下挟沙射流泥沙输运和沉降的动力机制，定量预测不同排放条件下底部污泥沉积体的成长速率和影响范围，为进一步开展复杂海洋动力环境下排海污水射流底泥的“二次污染”问题研究奠定基础。本项研究在丰富环境水力学的基本理论、完善污水海洋处置的关键技术、科学评价污水向海排放工程的环境效应等方面有着重要的理论意义和应用价值，也可为其他类型挟沙射流的研究提供有益的参考。

The sediment-laden jet is a typical two-phase flow which can be commonly found in nature or in engineering works. This study will focus on the low-concentrated sediment jet generated by the submarine outfall discharge, and pay a special attention on the sediment transport and deposition induced by either vertical or horizontal jet motion. The mechanisms of sediment transport and deposition under the combined effects of wave, current and jet motion are expected to be revealed. The instantaneous images of sediment patterns, which will be used to characterize the regional characters of the sediment-laden jet, will be discussed in detail. Besides, this project will concern the deposition rate of sediment nearby the jet nozzle, and propose a method to predict the affected area of sludge bank at the bottom. The outcome of this project will present a better understanding of the inter- dynamic mechanisms between the wave, current, jet and sediment, as well as the evolution of the sludge bank varying with the space and time. The research results are beneficial to the environmental assessment of the sub-marine outfall as well as the understanding of other types of sediment-laden jets.