六角形目和无结菱形目经编网片阻力性能与运动变化的比较

Comparative study on resistance characteristics and motion change of RHN and KRNDM

通过水槽模型实验，对六角形目经编网片（RHN）和无结菱形目经编网片（KRNDM）不同流速（V，0．5、0．75、1．0、1．25、1．5、1．75、2．0kn）、不同横向缩结系数（Et，0．60、0．65、0．707）下的网片阻力性能和运动变化进行了比较分析。结果如下：（1）网片固定时，六角形目网片阻力较大，无结菱形目网片阻力较小。在横向缩结系数范围（0．60～0．707）内，无结菱形目网片的阻力随着Et增大而逐渐减小，六角形目网片阻力则与Et变化无明显相关。（2）相同Et时，六角形目网片阻力始终较无结菱形目网片阻力大，且与无结菱形目网片之间的阻力差值随流速的增加逐渐增大。（3）Et对于水平位移和垂直位移的影响随网片的结构差异而不同。相同Et时，六角形目网片的水平位移均较大，无结菱形目网片较小。在设计选用网箱网片时（Et，0．60～0．707），首先应考虑网片网目结构和网线粗度，其次考虑横向缩结系数。

The Raschel Hexagonal Net （RHN）, the Knotless Raschel Netting in Diamond Mesh （KRNDM） were studied by the model test in the flume tank. Based on the comparison through change of hanging ratios （ Et ,0.60,0.65,0. 707 ） under different velocity of flow （ V,0. 5,0. 75,1. 0,1. 25,1. 5,1. 75,2. 0 kn）, the results of netting resistance characteristics and motion change （horizontal displacement and vertical displacement ） were obtained ： （ 1 ） The netting resistance of RHN was higher than that of the KRNDM under the test conditions of fixation. The resistance of Netting in Diamond Mesh was inversely proportional to the hanging ratio between the range 0.60 and 0. 707 during fixation, this function relationship is not significant in RHN. （2） The netting resistance of RHN was higher than that of KRNDM under the same Et, and the value difference between RHN and KRNDM increased with the increase of velocity of flow. （3） The variation of Horizontal Displacement（HD） is influenced by hanging ratios differed with net type. Under the same hanging ratios, the HD of RHN was higher than that of KRNDM. when designing the net（ E, ,0.60 - 0. 707 ） ,attention should first be paid to the net structure and line thickness then to the hanging ratio.