摘要
为探索圆形重力式网箱在动态流场中的水动力学特性,同时获得网箱系统内部与周围流场分布及流速变化规律,设计了4种不同网目形状和不同网目大小的网箱模型(C1、C2、C3、C4),选取4种不同水流流速(0.068 m/s、0.105 m/s、0.143 m/s、0.182 m/s),分别采用声学多普勒流速仪(ADV)和粒子图像测速(PⅣ)技术对网箱系统内外的流速及流场变化进行测定。结果表明,ADV试验与PⅣ技术测量结果基本一致;来流速度不同时,单个网箱范围内的水流衰减程度差异不大;来流速度相同时,小网目网箱的减流效果优于大网目网箱;网目大小相同时,菱形网目网箱减流效果优于方形网目网箱;群组网箱减流效果明显,且随着水流通过网箱数目的增加,网箱内与网箱后的流速降低明显,其中第2个网箱中心的流速衰减率已经达到了67.6%,第4个网箱中心的流速衰减率为88.2%,网箱后的流速衰减率为72.1%。研究结果可为养殖生产实践中网箱类型的选择提供理论参考。
In order to understand hydrodynamic characteristics of circular gravity net cage in varied flow field,and obtain both the flow velocity variations and flow field distribution inside and around net cages,four models （C1,C2,C3,C4） were designed to be measured at specific measurement points at a velocity of 0.068 m/s,0.105 m/s,0.143 m/s and 0.182 m/s by acoustic Doppler velocimeter （ADV） and particle image velocimetry （PIV） technique. The experimental data showed that the measurement result of ADV was basically the same with that of PIV tech-nique. The ratio of flow velocity reduction inside a net cage remained approximately the same in different flow velocities. On the effect of the flow velocity reduction,the net cages with small mesh did better than the net cages with big mesh,and the net cages with diamond mesh did better than the net cages with round mesh at the same flow velocity. As current flowed through multiple net cages,the flow velocity was gradually reduced. The flow velocity inside and downstream from the net cages decreased with increasing number of net cages. The flow ve-locity reduction was 67.6%inside the second net cage,88.2%inside the forth net cage,and 72.1%downstream from multiple net cages. This research can provide a reference to a suitable type of net cages used in aquaculture production practice.
出处
《中国工程科学》
北大核心
2014年第9期69-77,共9页
Strategic Study of CAE
基金
现代农业产业技术体系建设专项资金(CARS-50)
国家自然科学基金(31101938
51239005)
山东省科技发展计划项目(2009GG10005005)
关键词
网箱
ADV
PIV
流速
流场分布
net cage
ADV
PIV
flow velocity
flow field distribution
