心滩守护工程影响航道水流特性的数值模拟

Numerical simulation of impact from protection engineering for central bar on current characteristics

心滩是位于河心的浅滩,一般位于放宽河道内,会随水位涨落及水沙条件变化而十分不稳定,往往给航道条件带来十分不利的影响。为了改善航道条件,需要通过航道整治工程来稳定心滩,如软体排护滩工程、鱼骨坝护滩工程等。运用基于非结构三角形网格的平面二维水流数学模型对不同类型的心滩守护工程进行了研究。研究表明,建立的数学模型能够较好地模拟心滩周边的水流特性,较好地揭示了心滩守护工程对航道水流的影响特点,这对长江中下游航道涉及心滩的浅滩河段航道治理中具有一定的指导意义。

The central bar refers to the shoal located in the centre of the river. It is generally found in rivers with enlarged width and is very unstable with the stage fluctuations and changes in water and sediment conditions, which often results in very adverse impacts on the waterway conditions. In order to improve the waterway conditions, regulation projects of the waterway like the beach protecting project with soft mattress and the fish-bone dike project are absolutely necessary. This paper investigates different types of central bar protection projects based on two- dimensional mathematical model of water flow with unstructured triangular mesh method. The results indicate that the mathematical model proposed can capture the flow characteristics around the central bar very well, and further reveal the impact features of the central bar protection projects to the waterway flows which facilitates guiding significance to the regulation of the middle and lower reaches of the Yangtze River waterway with shoals and central bars.