General-Purpose Object-Oriented Framework for Vorticity-Dominated Flow Simulation

This paper describes the development of a computational framework for aerodynamic simulations based on the unsteady vortex lattice method under the object-oriented programming paradigm. The effort aims to fulfill the fluid-dynamics portion of the fluid-structure interaction problem in the multiphysics field. The construction and implementation of an object-oriented model is introduced along with its analysis and design stages, focusing on the generality and versatility. The overall class organization is presented, and the main classes' characteristics are discussed. The software validation indicates that the transient and the steady-state aerodynamics for the impulsively started motion of a body are accurately captured by the simulations. In addition, comparisons against experimental results show that rotors in hover flight are acceptably represented for small angles of attack of the blades, within the limitations of the flat-plate representation and the inviscid hypothesis of the model. Regarding applications, six different models are analyzed: 1) a single propeller rotor, 2) a small-scale quadcopter drone, 3) a flying-wing drone, 4) a joined-wing aircraft, 5) a drag-reduction system for cars, and, 6) a flapping-wing insect. In all cases, the results indicate that a well-tuned simulation based on vorticity-dominated flows is widely suitable for the aerodynamic study of several cases. All simulations expose the main advantages of a modular object-oriented program: the ability to change the case of analysis with minimal reprogramming, and the flexibility to link with different models in a co-simulation strategy.