Acoustical Broadband signatures from RANS Turbulence Quantities
2014 (English)In: The 21st International Congress on Sound and Vibration, 2014, 1541-1548 p.Conference paper (Refereed)
The high capacity of today's computers open up the possibility of using numerical simulations to provide a reliable support for optimization of the cooling module placed in heavy vehicles from both an acoustical and aerodynamic perspective. Typically the cooling compartment in heavy trucks consists of a large number of components building a complex, geometrically dense, package. Acoustically, adjacent surfaces are known to modify the sound level and the sound directivity caused mainly by the fan. For this reason, prediction of the sound sources and their radiation, using highly resolved turbulent numerical simulations, is still not feasible. In this paper, we present acoustic predictions that are based on results from Reynolds-Averaged Navier-Stokes (RANS) simulations on a given fan setup with the objective to identify noise characteristics from the turbulent quantities, using analytical expressions derived for isolated airfoils. The analytical formulas give the power spectral density (PSD) in the far-field associated with the noise mechanisms known as incoming turbulence noise and trailing edge noise both caused by the scattering of turbulent structures at the airfoil's leading- and trailing edge, respectively. In the fan setup, the fan was closely mounted to a shroud and placed in a wall between two adjacent rooms. Compared to the intricate underhood engine bay in a truck, the surrounding area affecting the acoustic radiation has been heavily reduced. Emphasis is to seize the apparent broadband trends previously measured in a facility customized for acoustical investigations. The fan studied is running at subsonic speed and consists of 11 blades, having a diameter of 0.75 m. The sound pressure level (SPL) calculated using the analytical expressions was found to show broadband properties previously captured during measurements.
Place, publisher, year, edition, pages
2014. 1541-1548 p.
Acoustic wave transmission, Acoustics, Airfoils, Navier Stokes equations, Numerical models, Power spectral density, Spectral density, Trucks, Turbulence, Acoustic predictions, Analytical expressions, Noise characteristic, Number of components, Power spectral densities (PSD), Reynolds-averaged navier-stokes simulations, Sound pressure level, Turbulent structures, Acoustic noise
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-157793ScopusID: 2-s2.0-84922601196ISBN: 9781634392389OAI: oai:DiVA.org:kth-157793DiVA: diva2:772069
The 21st International Congress on Sound and Vibration, 13-17 July, 2014 Beijing, China, 2014
QC 201412162014-12-162014-12-162016-09-05Bibliographically approved