关于渗流中流线不封闭的特性和条件

本文对于流体在多孔介质中流动的特性进行理论研究和数值计算，提出两个关于渗流中流线不封闭的特性和条件，得到了在一般工程实际情况中的多孔介质区域内部不存在封闭流线的结论。本文以突变截面圆管中不可压缩渗流为算例，利用半人工瞬变方法进行数值计算，得到流体在充满多孔介质的突扩截面圆管和突缩截面圆管中流动时关于速度分布和压力分布的结果。由此表明，在突变截面附近的渗流区域中不存在回流和分离流，也不存在封闭的流线。渗流的这些流动特性不同于在无多孔介质的空间区域中的流动特性。

Characteristics and Conditions of Unclosed Flow Streamline in Porous Media

The characteristics of the fluid fkw in porous media were theoretically studied and numerically computed in the paper. Two characteristics and conditions of unclosed flow streamline in porous media were presented. It is seen that there is no closed streamline in the porous media region in general engineering practical cases. Two examples of incompressible flow in porous media in the circular pipe with sudden-changed cross-section were numerically computed by the method of semi-false transient. The distributions of flow velocity and pressure in the circular pipe with sudden-enlarged and sudden-reduced cross-section were obtained. It is seen that there is no separated flow and closed streamline in porous media region near the sudden-changed cross-section. The flow characteristics in porous media region are different from those in space region, and there is not porous media.