本研究主要探討調節池之水理特性.影響調節池設計之因子很多,其中
開口型式與流量之關係為相當重要的一項,本研究以孔口流之射流理論為
基礎,配合前人之研究與實驗結果,求得流量修正係數之無因次參數,配合
定床水槽試驗加以分析探討,以求得在不同的出水 孔口徑,不同的排水孔
個數,以及排水孔在不同的排列方式下流量之變化.
本研究使用三座圓形開孔之滯洪壩從事水槽試驗.試驗項目分單孔不同口
徑,多孔水平排列及多孔上下交錯排列三類,一.單孔不同口徑:開孔口徑
為2.54公分,4.4公分,及7.2公分三種,在固定之底床坡度下,流量範圍
為0.066* ~5.88* cms.二.多孔水平排列:開孔口徑為2.54公分,開孔數為1
~8孔,在固定之底床坡度下,流量範圍為0.066* ~4.83* cms.三. 多孔上下
交錯排列:開孔口徑分4.4公分及7.2公分兩種,開孔數為1~5孔,在固定之底
床坡度下,流量範圍為0.13* ~22.85* cms.由試驗之數據分析,得其主要結
果如下: 一.由試驗之結果發現其流量係數並非為一定值,
會隨流量之增加而遞增. 二.在多孔水平排列之試驗中發
現,利用多個小出水孔來取代一大出水孔,其排除洪水將更 有效率,此
時所需設計之調節池蓄水體積將較小,可較節省工程經費.
三.設計水平排列之開孔時,在各開孔面積相同下,由實驗發現其總出流量
大於單一排水孔 之出流量乘上排水孔個數,為避免於設計出流量時其
值大於最大容許出流量,宜加一修 正係數以策安全.經試驗結果分析,
可獲得不同開口數下之流量修正係數.

The object of this study was to explore the hydraulic
characteristics of detention pond. The designation of detention
pond may be affected by many factors, especially the
relationship of the opening type of detention dam anddischarge.
After reviewing the paper, this study is based on the jet flow
theory of the orifice flow and find the discharge coefficient
which is dimensionless parameter through the analysis of
the dimension. With flume experiment under fixed slope, we
could find the varies of the discharge under many conditions
such as the different diameter,unequal numbers,and different
arrangement types of orifice.
This study used three detention dams with the circular orifice
in flume experiment. The tests are classified by three types.
The first type is the unique orifice with three different
diameters as 2.54cm, 4.4cm, and 7.2cm. The discharge is
between 0.000066~0.00588 cms. The second type is the
multipleorifice with horizontal arrangement, which has 1 to 8
opened holes, and all diameters of orifice are 2.54cm. The
discharge is between 0.000066~0.00483cms.The third type is the
multiple orifice with the up-down crossed arrangement. It has
two different diameters as 4.4cm and 7.2cm. Each of them has 1
to 5 opened holes. The discharge is between 0.00013~0.02285
cms. All tests are under the condition of the fixed slope of
the based bed. After analyzing
available data, the principle results were as follows: 1.The
discharge coefficient is variable and will increase when
discharge increases.
2.In the second type test, it would be more effectively to
drain flood using the multiple small holes in replacing of
one big hole, and the cost may decrease due to the smaller
volume of storage needed by retention pond. 3.In the
horizontal arrangement type test, we find that the total
outflow is larger than the outflow of the unique hole
multiplying by the hole number. For the sake of safety, we
should get the modified discharge coefficient. Through the
analysis of test data, the modified discharge coefficient for
different hole numbers could be gotten.