wangtiejun10 发表于 2009-5-19 19:29:10

水库挡水坝渗流边界问题

在水库挡水坝渗流分析中,具体见附件,AD上直接加降雨条件,BC不透水边界,AB边水位线以上我感觉应该用流量Q=0, CD边界以上应该加降雨,但感觉也不对,因为在靠近水位时的边界有降雨,也有可能水从此处渗出,不知道该怎么设置,希望版主,即高手指教,有对渗流感兴趣的朋友可以探讨,
我qq:402694331

basara 发表于 2009-5-20 16:07:51

瞬态分析?初始条件是左右两侧定义的水头(水头为零点的连线是初始水位线?),计算降水水位线的抬升?如果是的话,AB边水位线以上部分不需要定义边界,由计算得到。

wangtiejun10 发表于 2009-5-20 16:22:06

是瞬态分析,计算在降雨条件下孔压场地变化,我定义了cd水位线以上是流量检查边界,AB水位线以上是有可能渗流的,不设边界就是默认的不透水了,这样不合适吧

basara 发表于 2009-5-26 13:43:00

参考算例 Road ditch ponding during rainfall
你需要理解的是边界定义的三个重要的fundamental
1 A very important point to note is that boundary conditions can only be one of two options. We can only specify either the H or the Q at a node.
2 Another very important concept you need to fully understand is that when you
specify H, the solution to the finite element Equation 5-1 will provide Q. Alternatively, when you specify Q, the solution will provide H.
3 A third important fundamental behavior that you need to fully understood is that when neither H nor Q is specified at a node, then the computed Q is zero.
你认为在AB边界应该指定流量还是水头?显然,在这一边界只能是流量为0的边界what it means is that the flow coming towards a node is the same as the flow leaving the node.

basara 发表于 2009-5-26 13:53:41

本帖最后由 basara 于 2009-5-26 14:14 编辑

Seepage faces 边界也是非常重要的一类型边界
situations where neither H nor Q are known. A typical situation is the development of a downstream seepage face. 计算原理 在计算开始时边界上的Q is zero,每次迭代计算,将边界上节点孔隙水压力为正的点处的边界改为压力边界H equal to the y-coordinate (zero water pressure)。At the end of the repeated solution step, water can now leave or enter the system at the nodes that were converted from a Q-type to an H-type.

这类边界可以分析得到出溢点。

哥萨克 发表于 2010-10-11 14:59:24

Thanks for host's question and the 4#'s answers!!

lidongguang 发表于 2011-10-2 08:54:40

学习学习,谢谢~~

qinrong_0305 发表于 2013-6-4 21:23:52

正在学习中。。。
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