Simulation of Fan Broadband Noise

Seminar 15th January 2014 11 a.m. Building 7, Room 3019, Highfield Campus

Vincent Clair
Research Fellow ISVR

Submitter: Luke Goater

Vincent Clair

Vincent Clair (a new research fellow at the ISVR) will give a seminar on computational methods to predict broadband fan noise. The title and abstract of his presentation are copied below. The seminar will be in room 3019 in building 7, on Wednesday 15th January at 11:00, and it will be about 30 or 40 minutes followed by questions.

Title:

Numerical calculation of the acoustic response of a blade-row interacting with a turbulent wake

Abstract:

Noise generation due to rotor wakes impinging the stator vanes is a dominant turbofan source at approach conditions, and the broadband noise component is significantly contributing to the overall noise levels. A numerical method based on a code solving the Euler equations was developed in order to simulate the interaction noise between a turbulent wake and a vane row without geometry restrictions. The upstream turbulent flow is synthesized using a stochastic approach by considering an homogeneous isotropic turbulence spectrum model and a simplified spatial representation of the velocity field. These velocity gusts are injected in the Euler code by implementing a suitable boundary condition. The present methodology is first validated against turbulence-flat plate interaction cases, by comparing the numerical predictions to Amiet's solutions. An integral formulation is also used to assess the acoustic far-field. The method is then used to estimate the acoustic response of an isolated airfoil with a wavy leading edge, designed and tested in the ISVR wind tunnel in the framework of European project (FLOCON). Finally, the computations are extended to ducted annular grid configurations. After a validation on single-frequency cases described in a CAA benchmark, broadband noise simulations are performed, firstly on a flat-plate annular grid in a uniform axial flow tested in the LMFA wind tunnel, and then on a more complex configuration related to an unloaded grid in a swirling mean flow proposed by Atassi.