Large-Eddy Simulation of acoustic propagation in a turbulent channel flow

Numerical and theoretical investigation of pulsatile turbulent channel flows

“…However, the oscillation amplitudes a cl (ratio of the perturbation to the mean bulk velocity) in these simulations are relatively large for validation purposes (a cl = 0.7 in Scotti & Piomelli (2001), 0.2 in Comte et al (2006) and larger than 1 in Manna et al (2015)), which may challenge the linearization assumption in the proposed NEM. The onset of nonlinear effects is inevitable during the production and transportation of the Reynolds stress u i u j , and it results in higher harmonic components in u i u j other than its fundamental mode at the forcing frequency.…”

“…Such quasi-static models in general fail to describe the perturbation quantities (e.g. the wall shear stress) accurately, especially in the intermediate and higher frequency ranges (Scotti & Piomelli 2002;Tardu & Costa 2005;Comte et al 2006;Weng et al 2013).…”

“…Six forcing frequencies are chosen to cover the low, high and intermediate frequency ranges. The Reynolds number for the mean flow is Re τ = 350, which is chosen to be the same as in Scotti & Piomelli (2001) and Comte et al (2006) for convenience of comparison. The numerical results in the present study serve two purposes.…”

“…Direct numerical simulations/large eddy simulations (LES) have been performed for oscillating channel flows (Scotti & Piomelli 2001;Comte et al 2006) and pipe flows (Manna, Vacca & Verzicco 2012, 2015, and they provide valuable insight into the perturbation field in the turbulent boundary layer. However, the oscillation amplitudes a cl (ratio of the perturbation to the mean bulk velocity) in these simulations are relatively large for validation purposes (a cl = 0.7 in Scotti & Piomelli (2001), 0.2 in Comte et al (2006) and larger than 1 in Manna et al (2015)), which may challenge the linearization assumption in the proposed NEM.…”

Large Eddy Simulation of acoustic pulse propagation and turbulent flow interaction in expansion mufflers

“…Direct solution of the Navier-Stokes equations (DNS) could by definition provide accurate results in separating flow cases but would come at a very high computational cost and is not feasible for industrial applications. Large Eddy Simulation (LES), has however been demonstrated to be computationally feasible as a tool to study sound propagation [22][23][24][25][26].…”