Analysis on the hydrodynamic characteristics of Antarctic krill trawl otter board

LIU Jian;HUANG Hongliang;CHEN Yong;WU Xilei;WU Yue;CHEN Shuai;RAO Xin;LI Lingzhi;Engineering Technology Research Center of Marine Fishing,Chinese Academy of Fishery Sciences,Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation,Ministry of Agriculture,East China Sea Fisheries Research Institute,Chinese Academy of Fishery Sciences;Shanghai Kaichuang Deepsea Fisheries Co. ,Ltd.;

Antarctic krill trawl;;otter board;;hydrodynamic characteristics;;model test

For improving the expansion performance of trawl net in low trawling speed and enhancing the Antarctic krill trawl productivity,a high aspect ratio otter board with hollow structure was developed. A flume model experiment was conducted to measure the lift coefficient( CL),drag coefficient( CD) and lift to drag ratio( K) in different angle of attack( α). The experimental results are as follows: The CLand K value show a trend of increasing at the beginning and then decreasing with the increase of angle of attack,CDvalue reflects an upward trend with the increase of angle of attack; when α = 30°,the max lift coefficient( CLmax) is 1. 436,in this case CD= 0. 649,K = 2. 213; When α = 10°,the max lift to drag ratio( Kmax) is 4. 671,in this case CL= 0. 981,CD= 0. 210. Suggest the best working scope of angle of attack is between 10° ~ 30°,in which case,CL> 0. 98 and K > 2. 21. Through comparative analysis of the hydrodynamic performance of different types of otter boards,the Antarctic krill trawl otter board has advantages of lower drag coefficient and higher lift to drag ratio,which can provide a reference basis for further optimization of the Antarctic krill trawl otter board.