摘要
基于优化控制理论，以圆柱绕流的电磁控制为例，以减阻为目的，推导了流场优化控制的性能指标表达式和伴随方程，并对圆柱绕流的优化控制问题进行了数值研究，讨论了该优化控制下，流场和圆柱表面阻力和升力的变化过程。
The flow of the weak electrolyte solution can be controlled by Lorentz forces generated by the suitably chosen magnetic and electric fields, which holds the advantage for applications in the drag reduction, the suppression of vortex shedding and the vortex street in the flow over a bluff body. In order to get a large control effect with small power input, the interaction parameter N, the ratio of the electromagnetic force to the inertia force serving as control input in the control process, should be optimized according to the instantaneous flow field. In this paper, an adjoint-based ensemble optimization of control algorithms is developed for the drag reduction via Lorentz forces. A performance index based on the minimization of drag and adjoint equations in the expolential-polar coordinates are derived. Numerical simulations based on the NavierStokes equations and its adjoint equations for nonlinear optimal control of cylinder wake are carried out for Reynolds number Re = 150. The variations of the optimal interaction parameters with time are described based on calculation results and the evolutions of the flow field and the variations of the drag and lift forces on the cylinder surface in the control process are discussed.
出处
《空气动力学学报》
CSCD
北大核心
2007年第B12期97-101,共5页
Acta Aerodynamica Sinica
关键词
流体控制
伴随优化控制
电磁流体力学
flow control
nonlinear optimal control
electro-megnetic flow
