Numerical Study of Archimedes Propeller Configurations

This study presents numerical simulations of Archimedes propeller (AP) configurations with blade numbers ranging from two to five, while maintaining constant diameter and length. Delayed Detached Eddy Simulation (DDES) coupled with Shear Stress Transport (SST) k-𝜔 model is employed to resolve unsteady flow structures, and Ffowcs Williams-Hawkings (FW–H) acoustic analogy is used to predict farfield noise. The results reveal that propeller thrust is primarily governed by static pressure differences near the leading edge of the blades, while the helical blade geometry produces complex blade-vortex interactions, non-axisymmetric primary tonal noise directivity, and altered tip vortex trajectories. Increasing the number of blades reduces unsteady pressure fluctuations and blade-vortex interaction, resulting in lower noise signatures; however, this reduction comes at the cost of degraded propeller performance due to decreased inter-blade spacing which reduces the angle of attack on the blades due to the “tunnel” effect. A propeller tradeoff index is introduced to quantify the balance between propeller performance and noise, identifying the AP-4 configuration as the optimal design among all AP configurations under equal weighting. These findings provide new physical insights into the aerodynamic and aeroacoustic mechanisms of AP configurations in hover.