Aeroacoustic Noise Prediction Using the Fast Scattering Code

A set of perturbed compressible equations(PCE), based on a hydrodynamic/acoustic splitting method, is proposed for aeroacoustic noise prediction of low Mach number viscous flows. The present formulation corrects the deficiency of previous splitting methods that have no control over the coupling effects between the incompressible vorticity and the perturbed velocities. The validation test shows that the present PCE solution is in excellent agreement with those of direct acoustic numerical simulation(DaNS) and Curle's acoustic analogy for a laminar dipole tone from a 2D circular cylinder at Reynolds number based on the cylinder diameter, ReD=200 and free stream Mach number, M∞ = 0.3. Computational efficiency and accuracy requirements for PCE are also investigated for a vortex scattering noise from the trailing-edge of a thin plate at Reynolds number based on the plate thickness, Reh= 2000 and M∞ = 0.3. The test results indicate that the computational efficiency can be achieved with an acoustic grid at lower resolution, as long as the projection quality of the total derivative of the incompressible pressure, DP/Dt field is retained.

Download Full-text

Noise Prediction in Design of Low Pressure Rotor-Only Axial Fans

Volume 1: Advances in Aerospace Technology; Energy Water Nexus; Globalization of Engineering; Posters ◽

10.1115/imece2011-63044 ◽

2011 ◽

Author(s):

Jie Zhang ◽

Shaoping Zhou ◽

Xiaoling Ge

Keyword(s):

Sound Pressure ◽

Broad Band ◽

Low Pressure ◽

Noise Prediction ◽

Blade Design ◽

Prediction Program ◽

Aeroacoustic Noise ◽

Blunt Trailing Edge ◽

Axial Fans ◽

Semi Empirical

A noise prediction program has been incorporated into a blade design process of the arbitrary vortex flow rotor-only axial fans which are widely used in low pressure applications. Parametrical studies of different geometrical designs are conducted to investigate the influence on noise radiation from axial fans. The noise prediction program is based on the Carolus’s semi-empirical model, in which the broad-band aeroacoustic noise is mostly attributed to three independent sources: incident turbulence, turbulent boundary layer, and blunt trailing edge. In addition, the well-known Fukano’s vortex shedding model is also utilized for indicative comparison. It is indicated that the total sound pressure level is most sensitive to the flow relative velocity, while the chord length can be considered as a secondary cause.

Download Full-text

Perturbed Compressible Equations for Aeroacoustic Noise Prediction at Low Mach Numbers

AIAA Journal ◽

10.2514/1.3001 ◽

2005 ◽

Vol 43 (8) ◽

pp. 1716-1724 ◽

Cited By ~ 57

Author(s):

Jung-Hee Seo ◽

Young J. Moon

Keyword(s):

Noise Prediction ◽

Aeroacoustic Noise ◽

Mach Numbers

Download Full-text