Aeroacoustics of Subsonic Turbulent Shear Flows

A Composite Finite Difference Scheme for Subsonic Transonic Flows (RESEARCH NOTE).

This paper presents a simple and computationally-efficient algorithm for solving steady two-dimensional subsonic and transonic compressible flow over an airfoil. This work uses an interactive viscous-inviscid solution by incorporating the viscous effects in a thin shear-layer. Boundary-layer approximation reduces the Navier-Stokes equations to a parabolic set of coupled, non-linear partial diff...

Continued development of the one-way Euler equations: application to jets

An efficient method for calculating linearized disturbances to shear flows that accurately captures their acoustic radiation was recently introduced (Towne & Colonius, AIAA Paper 2013-2171, 2013). The linearized Euler equations are modified such that all upstream propagating acoustic modes are removed from the operator. The resulting equations, called one-way Euler equations, can be stably and ...

Modeling intermittent wavepackets and their radiated sound in a turbulent jet

We use data from a new, carefully validated, Large Eddy Simulation (LES) to investigate and model subsonic, turbulent, jet noise. Motivated by the observation that sound-source dynamics are dominated by instability waves (wavepackets), we examine mechanisms by which their intermittency can amplify their noise radiation. Two scenarios, both involving wavepacket evolution on time-dependent base f...

Numerical Simulation of Free Shear Flows- Towards a Predictive Computational Aeroacoustics Capability

Progress in direct noise computation

The needs for accurate and efficient numerical solvers in computational aeroacoustics have motivated the development of low-dispersion and low-dissipation schemes as an alternative to more classical methods of applied mathematics for computational fluid mechanics over the last two decades. These numerical methods have now reached maturity, even if progress is still necessary to take account of ...