聚乙烯网衣破损因素下的水动力特性与流场模拟

Hydrodynamic characteristics and flow field simulation study under the damage factors of polyethylene netting

海水养殖网箱网衣的完整性对于维护养殖效率和生态平衡至关重要。破损的网衣不仅会降低性能,还可能引起养殖生物逃逸,导致经济和生态的双重损失。为评估网衣破损对水动力特性及流场的影响,并探索损伤的初步定位和严重性评估方法,以指导网箱维护策略优化,建立了基于ANSYS Workbench的单向流固耦合数值模型,流体域中模拟网衣周围的流场,同时将网衣表面所受压力等数据传递到固体域,计算网衣在流体载荷作用下的变形和应力分布,获得了不同破损程度网衣在0.1~1 m/s流速下的流场特性及动力响应。结果显示:网衣阻力与流速呈二次方增长关系,破损程度的增加导致阻力下降,尤其在破损较大时阻力减小显著。流速衰减率在不同破损程度下相对稳定,表明网衣破损对整体流速衰减率的影响有限。在0.5 m/s流速条件下,破损网衣对前方流速衰减区影响有限,但破损使得网线间流速加快现象更明显,对后方流速衰减区造成显著干扰。网衣整体的最大变形与最大应力并未因破损程度的增加而显著变化,但破损区域附近的应力有明显增大。该研究不仅增进了对网衣水动力特性的理解,而且为海水养殖网箱的设计、性能评估和风险管理提供了重要的技术支撑。

The integrity of the netting in aquaculture cages is crucial for maintaining farming efficiency and ecological balance.Damaged netting reduces performance and may lead to the escape of cultured organisms,resulting in both economic and ecological losses.To assess the impact of netting damage on hydrodynamic characteristics and flow fields,and to explore preliminary methods for damage localization and severity assessment to guide the optimization of cage maintenance strategies,a unidirectional fluid-structure interaction numerical model based on ANSYS Workbench has been established.The model simulates the flow field around the netting in the fluid domain,obtaining data such as pressure on the netting surface,which is then transferred to the solid domain to calculate the deformation and stress distribution of the netting under fluid loads,achieving hydrodynamic responses of netting with varying degrees of damage at flow velocities of 0.1 to 1 m/s.The results show that the drag of the netting increases with the square of the flow velocity,and the increase in damage degree leads to a decrease in drag,especially when the damage is significant.The flow velocity decay rate is relatively stable under different damage degrees,indicating that the impact of netting damage on the overall flow velocity decay rate is limited.Under a flow velocity of 0.5 m/s,the influence of damaged netting on the flow velocity decay zone in front of the netting is limited,but damage makes the phenomenon of accelerated flow between the net lines more apparent,causing significant interference with the flow velocity decay zone behind.The overall maximum deformation and maximum stress of the netting do not change significantly with the increase in damage degree,but the stress near the damaged area increases significantly.This study not only enhances the understanding of the hydrodynamic characteristics of the netting but also provides important technical support for the design,performance evaluation,and risk management of aquaculture cages.