半无限长浅窄航道中船舶变速航行的有限元计算

Finite Element Calculation of Unsteady Flows Caused by Ship Moving with Varying Speed in a Half Infinite Retricted Shallow Waterway

在流体力学的基础上建立了船舶进入半无限长浅窄航道的数学模型 .由于船在狭航道中航行 ,研究的水的运动是一个变边界问题 ,采用浅水模型 ,半连船非惯性坐标系来计算变边界问题 ,让网格的变化来适应船的移动 ,开边界处使用辐射边界条件 .本文从非守恒型动量方程、二维浅水波动方程、连续性方程出发 ,采用有限元法计算船舶进入狭航道的水动力学过程 ;还研究了船和水体的相互作用 ,描述了自由水面波动、船底部的压力等重要物理量在船行驶过程中的变化规律 .给出了船进入狭航道时的水面波高图。

To study the moving of a ship in the shallow waterway, a kind of numerical model based on hydrodynamics is built in the paper. Because the ship is moving in the shallow waterway, the movement of water is changeable. Shallow water model and coordinate connected ship are taken to calculate the varying boundary. Let the movement of the grids adapt to the moving of the ship, a non_reflection boundary condition is imposed on open boundaries. The finite element methods based on non_conservation momentum equation, two_dimensional shallow water equation, and continuity equation are used. The interaction between the ship and water is studied also. The important variables, such as free surface elevation, horizontal velocity are calculated. 3_D free surface elevations pressure at the bottom of the ship are presented when a ship is moving in the narrow waterway.