摘要
弱电介质溶液中,电磁场产生的Lorentz力可以控制流体的运动。将其用于钝体绕流时,可以减少阻力、抑制分离和消除涡街。该文根据非线性优化控制理论,以圆柱绕流的电磁优化控制为例,以控制涡能为目的,推导了性能指标的表达式和伴随方程。基于棋手对弈时选择最佳落子的思路,通过求解流动方程和伴随方程,得到流场的非线性优化控制的解,即优化的电磁场强度的变化规律。讨论了优化控制下,绕流流场和圆柱表面阻力和升力的变化。结果表明:通过优化控制,可以达到减少阻力、消除涡街及涡生振荡的目的。
The flow of the weak electrolyte solution can be controlled by Lorentz forces generated by magnetic and electric fields, which facilitates the drag reduction, the suppression of vortex shedding and the vortex street of a bluff body. In this paper, based on the nonlinear optimal control theory, taking the enstrophy as the optimal performance index, the adjoint equations of cylinder wake via Lorentz force are developed. With the introduction of the ＇play chess＇ control method, numerical simulations based on the Navier-Stokes equations and their adjoint equations for nonlinear optimal control of cylinder wake are carried out. The variations of the optimal interaction parameters with time are obtained. The evolutions of the flow field and the variations of the drag and lift forces of the cylinder during the control process are discussed. It is shown that the reduction of drag force, suppression of vortex shedding and absorption of vibration are achieved by the optimal control.
出处
《工程力学》
EI
CSCD
北大核心
2009年第9期231-236,共6页
Engineering Mechanics
关键词
电磁流体力学
流体控制
优化控制
涡能
圆柱绕流
electromagnetic hydromechanics （EMHD）
flow control
optimal control
enstrophy
cylinder wake
