论文标题
粘性涡流对缸的相互作用在无粘性翻译平衡附近：数值研究
Viscous vortex-pair-cylinder interactions near inviscid translating equilibria: a numerical study
论文作者
论文摘要
使用晶格Boltzmann方法的数值模拟显示了以下二维不可压缩流问题。 Starting from configurations corresponding to translating inviscid equilibria, namely, the translating Föppl equilibria (counter-rotating point vortex pair, either fore or aft of a translating circular cylinder) and the translating Hill equilibria (counter-rotating point vortex pair, either fore or aft of an elliptic cylinder), viscosity is turned on for $t >0$ and the subsequent viscous interaction is模拟。相互作用是在动态耦合的设置中，中性浮力的圆柱体可以在其表面上瞬时流体应力的作用下沿对称轴自由移动。据观察，对于启动构型，涡旋对轨迹径径是圆柱体，粘性进化保持接近无粘性平衡。但是，对于启动涡旋对导致圆柱体引导的启动配置，与无粘性平衡存在明显的偏差。在这种情况下，涡流要么加速，要么将圆柱体留在后面，更有趣的是，将其领先的位置留在了尾随的位置上。换句话说，在这种情况下，气缸穿过领先的涡旋，超过它们，并且观察到涡流再次落下圆柱体。因此，关于垂直轴的无关动力学的对称性被损坏。
Numerical simulations using the Lattice Boltzmann Method are presented of the following two-dimensional incompressible flow problem. Starting from configurations corresponding to translating inviscid equilibria, namely, the translating Föppl equilibria (counter-rotating point vortex pair, either fore or aft of a translating circular cylinder) and the translating Hill equilibria (counter-rotating point vortex pair, either fore or aft of an elliptic cylinder), viscosity is turned on for $t >0$ and the subsequent viscous interaction is simulated. The interaction is in a dynamically coupled setting where the neutrally buoyant cylinder is free to move along the symmetry axis under the action of the instantaneous fluid stresses on its surface. It is observed that for starting configurations in which the vortex pair trails the cylinder, the viscous evolution stays close to the inviscid equilibrium. However, for starting configurations in which the vortex pair leads the cylinder, there is significant deviation from the inviscid equilibrium. In such cases, the vortices either accelerate and leave the cylinder behind or, more interestingly, leave their leading positions and are attracted towards the trailing positions. In other words, the cylinder in such cases threads through the leading vortices, overtakes them and the vortices are observed to trail the cylinder again. The symmetry of the inviscid dynamics about the perpendicular axis is thus broken.
