Computational aeroacoustic modeling of rotary mower noise

Abstract

The primary source of noise from rotary mowing machines is the aeroacoustic sound generated by the cutting blades. The requirements for maintaining high quality of the cut contradict those for reducing noise from the blade. The key to balancing these competing requirements is understanding the aeroacoustics of blades within the cutting environment. Until recently, there has been no reliable way to predict the noise generated by a configuration of blades and housing decks. To address this, John Deere and its partners have undertaken a program in Computational Aero‐Acoustics (CAA). By leveraging existing computational fluid dynamics and parallel processing capabilities, the participation of several software vendors, and the cooperation of industrial and academic partners, this project has provided a capability to accurately predict the sound generated by low Mach number flows in industrial systems. This presentation reviews the results of applying a nascent CAA capability. The noise generated by a single‐blade walk‐behind mower was computed and compares successfully with laboratory tests of radiated sound from the mower. Details of the computational process and the results will be presented.