Numerical Simulations of Serrated Propellers to Reduce Noise

Abstract

The objective of this research is to investigate the effect of serrations on quadcopter propeller blades on noise reduction through numerical simulations. Different types of the 5 inch 5030 propellers, such as the standard, modified and serrated, are tested. The modified propeller has a portion of its blade’s trailing edge cut off to achieve the same surface area as that of the serrated blades to ensure a fairer comparison. Three-dimensional simulations propellers have been performed using an immersed boundary method (IBM) Navier–Stokes finite volume solver to obtain the velocity flow fields and pressure. An acoustic model, based on the well-known Ffowcs Williams-Hawkings (FW-H) formulation, is then used to predict the far field noise caused by the rotating blades of the propeller. Results show that due to the reduction in surface area of the propeller’s blades, there is a drop in the thrust produced by modified and serrated propellers, compared to the standard one. However, comparing between the modified and serrated propellers with different wavelength, we found that certain wavelengths show a reduction in noise while maintaining similar thrust. This is because the serrations break up the larger vortices into smaller ones This shows that there is potential in using serrated propellers for noise reduction.