Noise Sources and Spectral Characteristics of the Tip-Jet Driven Rotor

• Published in: International journal of aeronautical and space sciences Vol. 22; no. 1; pp. 33 - 41
• Main Authors: Ko, Jeongwoo, Kim, Jonghui, Saravanan, Vignesh, Lee, Soogab
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Society for Aeronautical & Space Sciences (KSAS) 01.02.2021; 한국항공우주학회
• Subjects: Aerospace Technology and Astronautics; Engineering; Fluid- and Aerodynamics; Original Paper; 항공우주공학; Acoustic analogy; Tonal noise; Tip-jet driven rotor; Spectral characteristics; Noise sources
• ISSN: 2093-274X; 2093-2480
• DOI: 10.1007/s42405-020-00296-1

The noise sources of the tip-jet driven rotor are mainly classified as rotor blade noise and jet noise. The rotor blade noise includes thickness noise, loading noise, and nonlinear quadrupole noise, while the jet noise includes nozzle momentum noise and jet radiation noise. Each noise component has different noise source mechanisms related to flow characteristics and the rotating motion. Especially, the nozzle momentum noise has two noise source mechanisms based on the rotating steady aerodynamic load and the nozzle mass flow rate. The details of the time signal and spectrum are discussed to study the unique spectral characteristics. The tip-jet driven rotor noise has both tonal and broadband spectral characteristics. The periodicity of each instance of jet radiation noise is discussed, while the total jet radiation noise also has a tonal noise component. The noise source mechanisms and spectral characteristics are important considerations for an acoustically efficient tip-jet driven rotor.