Controlling chaotic dynamics of periodically forced spheroids in simple shear flow: Results for an example of a potential application

Recently, we studied the technologically important problem of periodically forced spheroids in simple shear flow and demonstrated the existence of chaotic parametric regimes. Our results indicated a strong dependence of the solutions.obtained on the aspect ratio of the spheroids, which can be used to separate particles from a suspension. In this paper we demonstrate that controlling the chaotic dynamics of periodically forced particles by a suitably engineered novel control technique, which needs little information about the system and is easy to implement, leads to the possibility of better separation. Utilizing the flexibility of controlling chaotic dynamics in a desired orbit irrespective of initial state, we show that it is theoretically possible to separate particles much more efficiently than otherwise from a suspension of particles having different shapes but similar sizes especially for particles of aspect ratio r(e) > 1.0. The strong dependence of the controlled orbit on the aspect ratio of the particles may have many applications such as in the development of computer-controlled intelligent rheology. The results suggest that control of chaos as discussed in this work may also have many applications.