方形箱网结构减流效果试验

根据降低流速对深水网箱养殖的影响这一需要,依据目前深水网箱的尺寸和渔具模型试验方法,设计并制作一个浮式箱网结构模型,同时进行水槽实验。实验在箱网的尾部设定一系列的断面和测量点,通过三维流速仪测量各点在不同实验流速下的流速,通过分析相关数据,探讨了该箱网减流结构尾部的流速分布和减流效果。实验流速采用了32.23 cm/s、50.19 cm/s、67.79 cm/s,分别相当于实际流速45.58 cm/s、70.79 cm/s、95.67 cm/s。实验测量了减流装置尾部减流区域50 cm到125 cm处的流速分布,相当于实际海域中距离减流装置尾部15 m到37.5 m处的流速分布。实验结果显示,箱网尾部的流速减小区域是在网箱网袋与来流垂直的投影面上,减流百分比在20%～45%左右,而箱网两侧的流速略有增加。从实验结果来看,这一结构能有效减小流速,通过合理的设计和在海域中布设,能够满足深水网箱养殖的减流需要。

Experimental study on effect of reducing current velocity by square net cage structure

A model square net structure was designed according to the dimension of deep-sea cage.The experiment was carried out in circular flume.The current velocity was surveyed using a 3D velocimeters set in front of the structure.The velocities at the positions behind the structure were also measured using the velocimeters.Then the data was analyzed,the effect of reducing current velocity was found out.The conclusions are:(1)The area of reducing current is located at the projection of net vertical to the current direction.The current velocity of both sides of cage increases a bit.(2)Testing velocities are 32.23cm/s,50.19cm/s and 67.79cm/s,which equal actual velocities 45.58cm/s,70.98cm/s and 95.67cm/s.The percentage of reducing velocity behind the square net structure is between 20% and 45%,which is close to the relative collusions.(3)Surveyed range is from 50cm to 125cm behind the structure,which equals actual range from 15m to 37.5m.The effect of reducing current velocity is apparent.