Numerical simulations on an articulated fish-like system

Numerical Simulations on an Articulated Fish-Like System

Figure 1. Multi-element system to emulate fish body.

The research on fluid dynamics of biomimetic is a challenging problem due to the complex hydrodynamic mechanisms of real aquatic animals. Although there are existing investigations on the fish swimming mechanisms by establishing the numerical and experimental models with typical kinematic motions, the understandings are still limited on the fish body internal forces and response to external forces. Inspired by the previous work of Kanso (2005) and Eldredge (2008) on the propulsion study for an articulated multi-segment system, we successfully developed a numerical strategy for simulating the fish body consisting multi-segments based on a method of coupling the Computational Fluid Dyanmics (CFD) and Multi-Body Dynamics (MBD).


Figure 2. Validation with the previous work.

The studies on the propulsion and maneuvering abilities provide essential insight for the design of swimming robots and AUV, and the research results will obviously contribute on the methodologies improvements and biomimetic understanding of internal and external forces response mechanisms.

With the use of this multi-element system to emulate fish body rather than using one specified travelling wave along body (Figure 1), the replication of the multiple degrees of freedom of real fish body along with the body internal inertial forces becomes feasible. The preliminary validation result in Figure 2 presents the feasibility and reliability of the in house code.

Figure 3. Snake-like robot Amphibot III.

The research interest is further developed on an integrated analytical-simulation frame work to model multi-segments robots, Amphibot III (Figure 3), by collaborating with the robotic team in Institut de Recherche en Communication et Cybernétique de Nantehas (IRCCyN). The task is to incorporating the dynamic model in Amphibot III into CFD codes, and the expected results can be seen as: a) visible flow field around the robot; b) detailed comparison and validation between CFD results and LAEBT analytical results.

For more information about the project contact  Dr Qing Xiao (, Lecturer at the Department of Naval Architecture and Marine Engineering at the University of Strathclyde.
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