Development and validation of a Vortex Particle code to evaluate Rotor and Propeller Performance

The efficiency of a lifting surface depends, among various things, on the downstream wake. In addition, the overall efficiency of an aircraft is strongly influenced by the wake of the lifting surfaces itself. This effect is evident if we consider the topic of propeller-based vehicles, which is nowadays widely gaining momentum in the community. Due to this increasing interest in the electric distributed propulsion for urban air mobility and UASs, it is relevant to find a fast yet reliable tool, to evaluate the performance of such propellers. Nevertheless, analyzing the flow field downstream of the propeller is a complex and time-demanding task, especially in the early stages of the design process, where an incorrect evaluation of these effects may have repercussions on many aspects of the project. This thesis proposes a relatively fast yet accurate algorithm to evaluate the flow field downstream of the propeller, based on the Vortex Particle Method, which became popular in the early 90s. The calculation performed by this method, the N body problem, involves a computational cost proportional to the square of the number of particles. In order to reduce the computational cost to one that is proportional to the number of particles, I implemented a Fast Multipole Method algorithm (FMM). FMM represents a vital tool to achieve acceptable computation times and possibly represents the key feature that makes this code a great compromise between the accuracy and the computational time. I have studied the integration of the FMM algorithm, written in C++, and the VPM code, written in MATLAB, to ensure that the communication between both codes does not represent a problem. In addition, I performed several simulations to check both the temporal advantage in the usage of the FMM and the method's accuracy. Moreover, throughout the entire work, I did a thorough validation and verification to ensure the best accuracy of the models used and the correct behavior of the code under all the possible configurations, both for the VPM code itself and the FMM integration. I am currently working on coding the tool into a stand-alone APP with a simple and understandable graphic user interface (GUI) to easily allow any user to use this code, even without a MATLAB license. This will help the diffusion of the code in the scientific community.