Unsteady Aerodynamics of Goal-Based Propulsion and Flight Employing CPFD

A fundamental aspect of the research is to study the interaction of vortices with structures and to consider efficiency, velocity, and thrust for the Unsteady Aerodynamic systems. The studies involve a vertical airfoil which is mounted to a carriage system, situated above a flowing water channel, which can propel itself in the fluid. This has represented a continuation and extension of our previous works, as well as novel research associated with self-propulsion. Key results from a comprehensive study on self-propulsion represent much of our current objectives. Our approach involves the use of the Cyber-Physical Fluid Dynamics (CPFD) facility to study aerodynamics of bodies with more than one degree-of-freedom motion. Although the research is fundamental, the results will be useful for the design of flapping-wing micro air vehicles, as one example, and we expect that new discoveries, phenomena and concepts will carry across to interesting problems that can be addressed with the CPFD Facility, not simply flapping wings. Much of our work is in vortex dynamics, and fundamental flow physics, and this is at the heart of those areas of flow research. The CPFD facility at Cornell is being used to study self-propulsion, with specified kinematics. There is no need to depend on tethered body investigations, because the CPFD facility can easily run self-propulsion experiments, without assumptions. We employ the CPFD facility and make use of contours in a "Heave-Pitch diagram". This is a simple idea where the y-axis of a plot represents pure heave, while the x-axis represents pure pitch, and inside these boundaries are controlled heave amplitude and controlled pitch amplitude, with contours of chosen variables; for example, vehicle velocity, or Propulsive Economy (efficiency), or maximum angle of attack during a cycle, or transverse impulse, etc. Although trivially easy to make these plots, it is nevertheless a powerful way to present the data as a set of related contour plots.