摘要
介绍了一种用于模拟水流作用下网箱受力变形的数值计算模型,并利用海上实测数据对计算模型进行了验证。验证结果表明,网箱锚绳力的计算结果与实测数据十分接近,最大相对误差为7.0%。在此基础上,分别对圆柱形网箱和圆台形网箱在不同配重(GW1=350 kg、GW2=600 kg)和流速(U=0.3~0.9 m/s)条件下所受的水流力以及容积损失率进行了数值计算。结果表明,两种网箱无论在所受的水流力方面还是在变形后保持的网箱容积方面随流速和配重的变化趋势基本一致。圆柱形网箱的容积损失率远大于圆台形网箱的容积损失率,在较小流速(U=0.3 m/s)研究时,圆柱形网箱的容积损失率达到了28%左右,具有较明显的初始变形。圆台形网箱的初始变形很小,具有较好的耐流特性和抗变形能力。
Deep-water net-cages made from HDPE,are the most widely used aquaculture facility among all kinds of anti-wave net-cages.They can be divided into cylinder net-cage and truncated-cone net-cage according to different net shapes.Comparing and analyzing the similarities and differences in the aspects of the forces and deformation between cylinder net-cage and truncated-cone net-cage,could help to provide a strong reference for the selection of cage style.Using lumped mass method and the rigid body kinematics principle,this paper described a numerical model including floating circular model as well as net model for simulating the force and deformation of net-cages in current,and the accuracy of simulation was validated by the data of marine in-situ measurements.By comparing,the numerical results of the mooring line forces on the cage were in good agreement with the in-situ test data,only 7% of maximum relative error and 4.6% of average relative error between them.The results indicated the numerical model and computational method adopted could meet the need of calculation accuracy for practical study.On the basis of that,under the conditions of two weight sizes(GW1 = 350 kg,GW2 = 600 kg) and five kinds of current velocities(U = 0.3-0.9 m /s),the drag forces and the volume reduction rate for cylinder net-cage and truncated-cone net-cage were calculated.In the process of simulating net,the mesh grouping method that 28 × 28 meshes have been combined into an equivalent large mesh,was applied to decrease computational time and improve efficiency.The results showed that after cages getting equilibrium in current,the two different cages in both drag force and cage volume kept the similar varying tendency with weight size or current velocity,only had little difference between them.The volume reduction rate of cylinder net-cage was much greater than that of truncated-cone net-cage.The cylinder net-cage had an obvious initial deformation when cage was only impacted by sinkers,the volume reduction rate of which was about 28% in relatively small velocity U = 0.3 m /s,but the truncated-cone net-cage had better anti-current and anti-deformation performances,with about 5% of volume reduction rate.Therefore,to decrease the loss of net volume in current as well as manufacturing cost,selecting truncated-cone net-cages with sinkers weight mode has more advantages than cylinder net-cages with that for aquaculture.
出处
《水产学报》
CAS
CSCD
北大核心
2011年第1期124-130,共7页
Journal of Fisheries of China
基金
国家"八六三"高技术研究发展计划(2010AA100301)
广东省科技计划项目(2008B021000042)
广东省海洋渔业科技推广专项项目(A200901G03)
中央级公益性科研院所基本科研业务费专项资金项目(2010YD09)
关键词
圆柱形网箱
圆台形网箱
受力变形
容积损失率
cylinder net-cage
truncated-cone net-cage
force and deformation
volume reduction rate