Optimal control of vortex shedding using low-order models. Part I - open-loop model development

An approach to developing active control strategies for separated ows is presented. The methodology pro- posed is applied to the incompressible unsteady wake ow behind a circular cylinder at a Reynoldʹs number of 100. Control action is achieved via cylinder rotation. Low-order models which are amenable to control and which incorporate the full non-linear dynamics are developed by applying the proper orthogonal decomposi- tion technique to data provided by numerical simulation. This process involves extensions to the usual POD approach and the results are therefore assessed for two `open-loopʹ test cases. The predictions are found to be satisfactory for control purposes, assuming the model can be reset periodically. The use of these models for optimal control is discussed in a companion paper, Part II. Copyright