Simulations of whistling and the whistling potentiality of an in-duct orifice with linear aeroacoustics

• Published in: Journal of sound and vibration 2012-02, Vol.331 (5), p.1084-1096
• Main Authors: Kierkegaard, A., Allam, S., Efraimsson, G., Åbom, M.
• Format: Article
• Language: English
• Subjects: Acoustics; Aeroacoustics; Aeroacoustics, atmospheric sound; Akustik; duct; Ducts; Engineering physics; Exact sciences and technology; Fluid dynamics; frequency-domain; Fundamental areas of phenomenology (including applications); General theory; linearized Navier-Stokes; Mathematical analysis; Methodology; Navier-Stokes equations; Physics; scattering; Simulation; Stability; TECHNOLOGY; TEKNIKVETENSKAP; Teknisk fysik
• ISSN: 0022-460X; 1095-8568; 1095-8568
• DOI: 10.1016/j.jsv.2011.10.028

This paper demonstrates a linear aeroacoustic simulation methodology to predict the whistling of an orifice plate in a flow duct. The methodology is based on a linearized Navier–Stokes solver in the frequency domain with the mean flow field taken from a Reynolds-Averaged Navier–Stokes (RANS) solution. The whistling potentiality is investigated via an acoustic energy balance for the in-duct element and good agreement with experimental data is shown. A Nyquist stability criterion based on the simulation data was applied to predict whistling of the orifice when placed in a finite sized duct and experiments were carried out to validate the predictions. The results indicate that although whistling is a nonlinear phenomena caused by an acoustic-flow instability feed-back loop, the linearized Navier–Stokes equations can be used to predict both whistling potentiality and a duct system's ability to whistle or not. ► An aeroacoustic simulations methodology based on the frequency domain Navier–Stokes equations are presented. ► A Nyquist stability criterion was applied to identify whistling in duct systems. ► Simulation results are validated by experiments, with good agreement. ► Results suggest that linear aeroacoustic simulations can be used to predict whistling in duct systems.