Session: 03-02-01 Bio-Inspired and Biomedical Fluid Mechanics

Paper Number: 87645

87645 - Body Shape Effects on the Hydrodynamic Performance of Bio-Inspired Undulating Swimmers 

Numerous studies have been completed understanding the impact of the movement parameters and their effect on propulsive performance in fish-like swimming. These studies led to an understanding of how fish-like swimmers are impacted by changes in movement both individually and in schools. In this research, we parametrically study the effects of the fish body shape on the hydrodynamic performance of carangiform fish swimming both individually and in a school.

 To complete the parametric study, we use a class shape transformation (CST) parameterization method to create two-dimensional fish body shapes. Through this method, we break down the airfoil into six coefficients that correspond to thickness at different points along the chord of the airfoil. The CST maintains the core airfoil shape and allows us to change the thickness in specific regions of the airfoil with a few inputs. Using this method, we vary the maximum thickness, maximum thickness location along the foil, leading edge radius, and boattail angle of the fish bodies. We then use an in house immersed boundary method-based incompressible flow solver to compute the wake structure and performance coefficients of the fish. In this solver, the Navier-Stokes equations are discretized using a cell-centered, collocated arrangement of the primitive variables and are solved using a finite difference-based Cartesian grid immersed boundary method. The results are shown by the net thrust and drag on the fish body, as well as the power utilized by the fish during the motion.

In the results, we will show that changing the body shape of a fish in carangiform swimming leads to significant changes in its performance. Finally, the results will show how the shape changes affect the performance of an inline two fish school and a diamond four fish school. These results will contribute to a better understanding of fish body shape in single fish swimming and schools, as well as better informing the design of bio-inspired underwater robots.

Presenting Author: John Kelly University of Virginia