Hydrodynamic response analysis of Antarctic krill trawl with pump suction pipe configuration

To investigate the optimal configuration of the pump suction pipe in continuous pump suction Antarctic krill beam trawls, we took the beam trawl used by the specialized Antarctic krill fishing and processing vessel "Deep Blue" as the research object. Based on the modified Tanaka criterion, we established trawl models with large and small scale ratios of 15 and 5, respectively. In a circulating flume tank, experiments were conducted to test the effects of the pump suction pipe's deployment position, internal diameter, and reserved length on the drag, geometry, and stability of the beam trawl model. The results showed that: 1) Deploying the pump suction pipe above the side net yielded the maximum mouth height of the beam trawl. When placing it below the belly net, the overall drag of the beam trawl was the minimum. However, when the pump suction pipe was positioned above the upper net, the force difference on both sides of the beam trawl was the minimum, and the energy consumption coefficient reached its lowest level. 2) Increasing the internal diameter of the pump suction pipe had no significant effect on the net mouth height but increased drag and the energy consumption coefficient. When the internal diameter increased from 16 mm to 26 mm, drag increased by 7.69%, and the energy consumption coefficient increased by 8.44%. 3) The reserved length of the pump suction pipe had no significant impact on the net mouth height of the beam trawl. A shorter reserved length of the pump suction pipe maintained the drag-energy consumption for the beam trawl, while a longer one led to increased drag and energy consumption. 4) Deploying the pump suction pipe above the upper net, while reducing its internal diameter and reserved length, resulted in the smallest drag fluctuation amplitude and the highest stability. This study can provide a basis for optimizing the pump suction pipe configuration and the structural design of Antarctic krill trawl fishing gear.