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 periodic ally forced spheroids in simple shear flow and demonstrated the existe nce of chaotic parametric regimes. Our results indicated a strong depe ndence of the solutions.obtained on the aspect ratio of the spheroids, which can be used to separate particles from a suspension. In this pa per we demonstrate that controlling the chaotic dynamics of periodical ly forced particles by a suitably engineered novel control technique, which needs little information about the system and is easy to impleme nt, leads to the possibility of better separation. Utilizing the flexi bility of controlling chaotic dynamics in a desired orbit irrespective of initial state, we show that it is theoretically possible to separa te particles much more efficiently than otherwise from a suspension of particles having different shapes but similar sizes especially for pa rticles of aspect ratio r(e) > 1.0. The strong dependence of the contr olled orbit on the aspect ratio of the particles may have many applica tions such as in the development of computer-controlled intelligent rh eology. The results suggest that control of chaos as discussed in this work may also have many applications.