Abstract
The drag of the net is the main component of the total hydrodynamic loads of the cage. Net drag is related to the safe use and reliability of the net cage. However, there is still a lack of tests about the influence of different parameters such as materials, mesh types, solidity ratios, and angles of attack on the hydrodynamic loads of nets. In this paper, a series of flume tests are used to investigate the drag on the nets and the relationships between the drag coefficient and the net material, net solidity ratio, mesh shape, current velocity, and current direction. The drag of six nets with different types under varying current velocities and current directions are calculated, and the curves between the drag coefficient and the current velocity or Reynolds number are further obtained. The test results show that the drag and drag coefficients of the net are not only related to the current velocity and the windward area but also to the mesh shape, net solidity ratio, material properties, etc. On this basis, the drag coefficients of these nets obtained from the prediction models and the tests are compared and analyzed, and the applicable conditions of different prediction models are further clarified. This paper can provide data support for the drag calculation of the cage.