NAFEMS Americas and Digital Engineering (DE) teamed up (once again) to present CAASE, the (now Virtual) Conference on Advancing Analysis & Simulation in Engineering, on June 16-18, 2020!
CAASE20 brought together the leading visionaries, developers, and practitioners of CAE-related technologies in an open forum, unlike any other, to share experiences, discuss relevant trends, discover common themes, and explore future issues, including:
-What is the future for engineering analysis and simulation?
-Where will it lead us in the next decade?
-How can designers and engineers realize its full potential?
What are the business, technological, and human enablers that will take past successful developments to new levels in the next ten years?
Resource AbstractFSI Analysis of an Autonomous Underwater Vehicle in Oscillating Motion
The development of Autonomous Underwater Vehicle (AUV) systems has progressed significantly in the past decade. These systems are being designed to be thrust efficient and highly maneuverable by aiming to reproduce the fish-like locomotion mechanism. Additionally, some recent studies have investigated the energetic benefits of individual fish swimming near an obstruction or swim in tandem with other fish. For an individual fish, obstructions or other fish create flow conditions and eddies that fish can benefit from to reduce the energetic cost of holding station in water.
The flow physics in the vicinity of the oscillating flexible body can be significantly different than flow physics observed over a single rigid body. Furthermore, the kinematics of oscillation as well as maneuvers result in highly coupled nonlinearities in fluid dynamics and structural dynamics. Therefore, it is believed that fluid-structure interaction simulation is needed for AUV systems with flexible characteristics, and the FSI approach can increase the accuracy of such vehicles compared to computational fluid dynamics alone. The FSI approach considered in the present study will be strongly coupled, nonlinear, and multidisciplinary, which would require a strong numerical coupling approach.
The present study is set to investigate the propulsion characteristic differences of a fish-like AUV system with flexible material compared to one with rigid material. Both configurations have their tails set in oscillating motion and placed in a low Reynolds numbers water flowing in a channel. Similar exercises with flexible and rigid airfoils set in oscillating motion have already been completed in the first phase of the study. In the first phase, we investigated a two-dimensional NACA 0012 airfoil set in purely sinusoidal pitching motion with the axis of rotation at the quarter-chord point The configuration used in this investigation is a two-dimensional NACA 0012 airfoil set in purely sinusoidal pitching motion with the axis of rotation at the quarter-chord point at various angles of attack, pitching frequency, and pitching amplitude. The comparison of FSI simulation results indicated flexible airfoil clearly outperforming the rigid airfoil at about 57% for the range of conditions considered.
The enhanced propulsion of the flexible material is likely due to larger trailing-edge vortices generated when the flexible material is used. The comparison of the streamlines for both rigid and flexible material shows that for the same conditions (similar Re, k, and ), flexible material produced larger trailing-edge vortices.
