Numerical design of the forces generated by a collective and cyclic pitch propeller - force magnitude and phase shift

A novel propulsion and manoeuvring system for Autonomous Underwater Vehicles (AUVs), the collective and cyclic pitch propeller (CCPP), has been the focus of recent (numerical) research efforts. The CCPP offers advanced control of the blade pitch to provide effective and efficient propulsion and manoeuvring forces at both high and low forward velocities. The current paper reports on ongoing research, using a three-dimensional periodic unsteady RANS-based numerical model expanded and aims to (re-)design the forces generated by the CCPP. The force design focuses on the generation of an effective and efficient manoeuvring force or side-force, as quantified by the side-force magnitude and phase shift, respectively. The results, evaluating the effect of a range of collective and cyclic pitch angles, established that at high (collective) pitch angles, the generation of a combined effective and efficient side-force becomes impossible. As the pitch angles become larger, large forces are generated but the occurrence of the associated drag makes the force generation highly inefficient, i.e. a large phase shift occurs. The threedimensional periodic methodology does prove its ability to analyse and design the forces involved and will be used for further design optimisation, aiming to increase the generated side-force magnitude at lower pitch angles.