Analysis of Sound Pressure Radiated from Vibrating Beam

Prediction of radiated sound power from vibrating structures using the surface contribution method

A common measure for near-field acoustic energy of a vibrating structure is the acoustic intensity, which usually has positive and negative values that correspond to energy sources and sinks on the surface of the radiating structure. Sound from source and sink areas partially cancel each other and only a fraction of the near-field acoustic energy reaches the far-field. In this paper, an alterna...

Analysis of motor fan radiated sound and vibration waveform by automatic pattern recognition technique using “Mahalanobis distance”

In recent years, as the weight of IT equipment has been reduced, the demand for motor fans for cooling the interior of electronic equipment is on the rise. Sensory test technique by inspectors is the mainstream for quality inspection of motor fans in the field. This sensory test requires a lot of experience to accurately diagnose differences in subtle sounds (sound pressures) of the fans, and t...

Analytical Solution for Sound Radiation of Vibrating Circular Plates coupled with Piezo-electric Layers

In the present study, the classical plate theory (CPT) was used to study sound radiation of forced vibrating thin circular plates coupled with piezoelectric layers using simply supported and clamped boundary conditions. The novelty of the study consists of an exact closed-form solution that was developed without any use of approximation. Piezoelectric, electrical potential loaded in the transve...

Validation of acoustic-analogy predictions for sound radiated by turbulence

Effects of compliant coatings on radiated sound from a rigid-wall turbulent boundary layer

A theoretical model is developed to investigate the effect of compliant coatings on radiated sound from low Mach-number turbulent boundary layers over otherwise rigid surfaces. Lighthill’s analogy is employed and the primary noise source is assumed to be from wall-pressure fluctuations. Parametric studies are performed on the behavior of the material properties such as the speed of sound and de...