关键词: Momentum redistribution method, OpenFOAM, Fluid–Structure Interaction (FSI), Immersed Boundary Method (IBM), Anguilliform swimming, Manta bot

Abstract: This paper presents an efficient and versatile OpenFOAM (Open-source Field Operation And Manipulation)-based numerical solver for fully resolved simulations that can handle any rigid and deforming bodies moving in the fluid. The algorithm used for solving Fluid–Structure Interactions (FSI) involving the immersed structure with changeable shapes is based on the momentum redistribution method. The present approach excludes the need to solve elastic equations, obtain high-accuracy predictions of the flow field and provide a rigorous basis for implementing the Immersed Boundary Method (IBM). The OpenFOAM implementation of the algorithm is discussed along with the design methodology for developing bio-inspired underwater vehicles using the present solver. The computational results are validated with the experimental observations of the two-dimensional and three-dimensional anguilliform swimmer case studies. The study further extended to the three-dimensional hydrodynamics of a bioinspired, self-propelling manta bot. The motion of the body is specified a priori according to the reported experimental observations. The results quantify the vortex formation and shedding processes and enable the identification of the portions of the body responsible for the majority of thrust. The body accelerates from rest to an asymptotic mean forward velocity of 0.2 ms?1 in almost 5 s, consistent with experimental observations. It is observed that the developed computational model is capable of performing any motion simulation and manoeuvrability analysis, which are critical for the designers to develop novel unmanned underwater vehicles.

Key words: Momentum redistribution method, OpenFOAM, Fluid–Structure Interaction (FSI), Immersed Boundary Method (IBM), Anguilliform swimming, Manta bot