The Flow Around A Cylinder Electromagnetic Control And Optimization

Electromagnetic control of cylinder wake and its optimality has been investigated in the present thesis. First of all, an electrode pulsing controller which can provide a reliable experiment flat for electromagnetic optimal control has been designed and developed. Secondly, based on the Maxwell equations of the electromagnetic fields, the distributing characteristics of the electromagnetic field and the electromagnetic force on the surface of electromagnetic actuator with cylindrical shape in a moving low-conducting electrolyte have been obtained by numerical simulations, which can provide the basic data to electromagnetic optimal control. Lastly, optimal control of cylinder wake has been simulated and discussed according to optimization control algorithms.Electrode pulsing controller is a very important device to produce Lorentz force in a traveling wave, which has been designed and developed in the present thesis. The controller integrates the control circuit reliability with graphical user interface. The space distribution and sequence of electromagnetic force can be changed conveniently. Consequently, an expedient experiment flat can be obtained for the investigation on constant electromagnetic force control to the investigation on time-variable electromagnetic force control. Secondly, according to the basic equations in the electromagnetic fields, the electric and magnetic potential, electric field, magnetic field and Lorentz forces induced by the actuator with cylindrical shape in a moving low-conducting electrolyte were calculated numerically, which provide an important reference for electromagnetic optimal control. Lastly, the variations of the optimal interactions parameters with time are described based on the optimal control theory on the flow field developed by Bewley. The reduction of drag force and suppression of vortex shedding on a circular cylinder in the electrically low-conducting water can be realized by utilizing the optimal Lorentz forces, consequently, the cylinder wake has been controlled efficiently.Tested in several experimentations, the electrode pulsing controller designed and investigated can be used on electromagnetic flow control of cylinder wake and it can satisfy the requirement of experimentations. Furthermore, the numerical simulation of electromagnetic optimal control of cylinder wake can guide our future experimentations.