Characterization of sound scattering using near-field pressure and particle velocity measurements.

J Acoust Soc Am

Acoustic Technology, Department of Electrical Engineering, Technical University of Denmark (DTU), Building 352, DK-2800 Kongens Lyngby, Denmark.

Published: October 2019

The acoustic properties of surfaces are commonly evaluated using samples of finite size, which generate edge diffraction effects that are often disregarded. This study makes use of sound scattering theory to characterize such finite samples. In a given sound field, the samples can be described by a unique complex directivity function called the far-field pattern. Numerical results show that the far-field pattern contains extensive information on the tested samples, including sound absorption and surface scattering, as well as scattering due to finiteness. In this paper, a method is introduced to estimate the far-field pattern of a finite sample. The method relies on measurements of the sound pressure and acoustic particle velocity in the near-field of the sample, and it makes use of the Helmholtz integral equation. The proposed technique is examined in an anechoic room where the sound field near the test sample is scanned with a three-dimensional sound intensity probe. The estimated far-field pattern is compared with numerical predictions up to 1 kHz.

Download full-text PDF

Source
http://dx.doi.org/10.1121/1.5126942DOI Listing

Publication Analysis

Top Keywords

far-field pattern
16
sound scattering
8
particle velocity
8
sound field
8
sound
6
characterization sound
4
scattering
4
scattering near-field
4
near-field pressure
4
pressure particle
4

Similar Publications

Stretchable electromagnetic interference (EMI) shields with strain-insensitive EMI shielding and Joule heating performances are highly desirable to be integrated with wearable electronics. To explore the possibility of applying geometric design in elastomeric liquid metal (LM) composites and fully investigate the influence of LM geometry on stretchable EMI shielding and Joule heating, multifunctional wrinkle-structured LM/Ecoflex sandwich films with excellent stretchability are developed. The denser LM wrinkle enables not only better electrical conduction, higher shielding effectiveness (SE) and steady-state temperature, but also enhanced strain-stable far-field/near-field shielding performance and Joule-heating capability.

View Article and Find Full Text PDF

Interference of surface plasmons has been widely utilized in optical metrology for applications such as high-precision sensing. In this paper, we introduce a surface plasmon interferometer with the potential to be arranged in arrays for parallel multiplexing applications. The interferometer features two grating couplers that excite surface plasmon polariton (SPP) waves traveling along a gold-air interface before converging at a gold nanoslit where they interfere.

View Article and Find Full Text PDF

The following paper presents the findings of a study conducted on the distances at which the field generated by a ϕ-symmetric circular Taylor aperture distribution can be classified as far-field, and also the efficiency across various study parameters. The [Formula: see text] transition integers that produce a monotonic distribution, which have been traditionally used and analyzed, are compared with those that yield a peaked distribution, and offer greater efficiency. Additionally, modified circular Taylor [Formula: see text] distributions featuring synthesized patterns with one or two depressed inner sidelobes, which have not been previously explored, are also examined.

View Article and Find Full Text PDF

Scaffolds are of great interest in tissue engineering associated with regenerative medicine owing to their ability to mimic biological structures and provide support for new tissue formation. Several techniques are used to produce biological scaffolds; among them, far-field electrospinning (FFES) process is widely used due to its versatility in producing promising structures similar to native tissues owing to the electrospun nanofibers. On the other hand, near-field electrospinning (NFES) has been investigated due to the possibility of creating scaffolds with suitable architecture for their use in specific biological tissues.

View Article and Find Full Text PDF

Surface angled cracks on critical components in high-speed machinery can lead to fractures under stress and pressure, posing a significant threat to the operational safety of equipment. To detect surface angled cracks on critical components, this paper proposes a "Quantitative Detection Method for Surface Angled Cracks Based on Full-field Scanning Data". By analyzing different ultrasonic signals in the full-field scanning data from laser ultrasonics, the width, angle, and length of surface angled cracks can be determined.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!