船舶表面微结构设计及其减阻性能分析
Ship Surface Microstructure Design and Its Drag Reduction Performance Analysis

针对船舶航行时水下表面存在微结构时，可减小阻力、提升能源使用效率的特点，以鲨鱼皮表面为仿生基础，设计仿鲨鱼、V形、矩形三种微结构表面，通过Fluent软件进行数值模拟，探究不同微结构形状对近壁区表面减阻率、剪切力、速度和湍流动能的影响。数值模拟结果表明：与无结构表面相比较，不同沟槽形状的微结构表面都具备一定的减阻性能。相较于仿鲨鱼、V形微结构表面，矩形微结构表面的减阻效果最好，速度为1 m/s时减阻率最高可达18.4%。微结构的存在可以有效地减小表面所受到的壁面剪切力，减缓近壁边界层的速度梯度变化，改善流体在近壁区域内的流动情况，减少能量涡旋。
In view of the fact that the presence of microstructures on the underwater surface during ship navigation can reduce the drag force and improve the efficiency of energy use, three microstructured surfaces, namely, shark-like, V-shape, and rectangular, are designed based on the sharkskin surface, and numerical simulations are carried out by Fluent software to investigate the effects of different microstructured shapes on the surface drag reduction rate, shear force, velocity, and turbulent kinetic energy of the surface in near-wall area. The numerical simulation results show that the microstructured surfaces have certain drag reduction performance compared with the unstructured surfaces. Compared with the shark-like and V-shaped microstructured surfaces, the rectangular microstructured surface has the best drag reduction effect, with a maximum drag reduction rate of 18.4% at a velocity of 1 m/s. The presence of microstructures can effectively reduce the shear force and the turbulence kinetic energy. The existence of microstructures can effectively reduce the wall shear force on the surface, slow down the change of velocity gradient in the boundary layer in the near-wall region, improve the flow of fluid in the near-wall region, and reduce the energy vortex, so it has a certain drag reduction performance.