Assessment of combustion noise in a premixed swirled combustor via Large-eddy simulation

Today, much of the current effort in combustion noise is the development of efficient numerical tools to calculate the noise radiated by flames. Although unsteady CFD methods such as LES or DNS can directly provide the acoustic field radiated by noise sources, this evaluation is limited to small domains due to high computational costs. Hybrid methods have been developed to overcome this limitation. In these schemes, the noise sources are decoupled from the radiated sound. The sources are still calculated by DNS or LES codes whereas the radiated sound is evaluated by acoustic codes using an acoustic analogy. In the present paper the assessment of combustion noise is conducted by both direct (LES) and hybrid computations in a premixed swirled combustor. Some comparisons of the sound pressure levels resulting from both approaches are shown, and the main differences between the two methods are explained. keywords: combustion noise, acoustic analogy, direct computation, hybrid computation.