A METHOD FOR ESTIMATING THE INNER SHAPE OF CYLINDERICAL NET- FISH CAGE

The healthy, quality of the cultured species inside a cage lies on extent of fiber net deformation under rough environmental conditions where the cage installed. So, it is important to estimate inner shape of the cylindrical net. This helps to find issues in advance and provide opportunity for design improvement. In this study, a mathematical model proposed for estimating the shape of netting at any current conditions. A cage is composed of flexible structure: netting and rigid structures including floating collar, sinking collar. The extent of the constriction of the net depends on cage structure, and design of the mooring systems, external and internal forces acting on the members of the cage. The vertical extension of the netting structure lies on the weight in water of the sinker. Horizontal extension, bending and constrictions lies on the current velocity and stiffness of the fiber of the netting. Moreover, the deflections of the front half of the net and the rear half net is proportional to the incoming current speed to cage and inner (filtered) current speed.  The calculated figures using this model compared with observed values obtained from the flume tank test at same flow current speed ranging from 0.1 to 1.0m/s at 0.1m/s and with other previously proposed models.