This study is aimed to investigate the bio-mimetic swimmer propulsion mechanism with the use of its internal muscle force. A simplified articulated model, with multiple rigid segments connected by the joints (imitating the muscle force), is adopted to represent the real swimmer body. To modeling the problem, a Computational Fluid Dynamics (CFD) method is coupled with the system dynamic equations. Some preliminary results obtained showed that the numerical methods developed are able to predict the self-propelled articulated multi-body system with multiple degrees of freedom.Copyright © 2013 by ASME