Work

Lighthill’s Theory of Sound Generation in Non-Isothermal and Turbulent Fluids

Year: 2025

Type: article

Abstract: Lighthill’s theory of sound generation was developed to calculate acoustic radiation from a narrow region of turbulent flow embedded in an infinite homogeneous fluid. The theory is extended to include a simple model of non-isothermal fluid that allows finding analytical solutions. The effects of one specific temperature gradient on the wave generation and propagation are studied. It is shown that the presence of the temperature gradient in the region of wave generation leads to monopole and dipole sources of acoustic emission and that the efficiency of these two sources may be higher than Lighthill’s quadrupoles. In addition, the wave propagation far from the source is different than in Lighthill’s original work because of the presence of the acoustic cutoff frequency resulting from the temperature gradient.

Source: Fluids

DOI: 10.3390/fluids10060156

Authors: Swati Routh, Zdzislaw E. Musielak

Institutions: Birla Institute of Technology and Science, Pilani - Dubai Campus, The University of Texas at Arlington

Language: English

Topic: Aerodynamics and Acoustics in Jet Flows

Subfield: Aerospace Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,172

Funder: Birla Institute of Technology and Science, Pilani