Engineering topics

Logan T. Mathews

Publications and source records attributed to Logan T. Mathews.

3 records

NASA NTRS2020

Development of a Weather-Robust Ground-Based System for Sonic Boom Measurements

This report describes Brigham Young University’s (BYU) development and testing of a weather-robust, ground-based system for sonic boom measurements, carried out in support of NASA’s Quiet Supersonic Flight (QSF) initiative. The microphone configuration system, referred to as the Compact Outdoor Unit for Ground-based Acoustical Recordings (COUGAR, for the BYU mascot), was tested at NASA’s 2018 Quiet Supersonic Flight (QSF18) campaign and at the subsequent 2019 Carpet Determination in Entirety Measurements (CarpetDIEM) program.

sonic boom↗

NASA NTRSDate not supplied

Comparing Two Weather-Robust Microphone Configurations for Outdoor Measurements

This paper discusses comparisons made between two ground-based outdoor microphone configurations. The first is known as the Compact Outdoor Unit for Ground-based Acoustical Recordings (COUGAR) and consists of an inverted microphone placed above a convex circular plate and covered by a large dome windscreen. The second configuration is the COUGARxt, where the “xt” simultaneously refers to an extra thick windscreen and an extra thin ground plate. COUGAR and COUGARxt were subjected to laboratory testing where their responses to sound were recorded at several different elevation and azimuthal angles. At almost all shown elevation angles, both configurations recorded levels that were within ±3 dB of a baseline measurement between 50 Hz – 20 kHz. At all shown azimuthal angles and over the same frequency range, both recorded levels within ±2 dB of the levels reported at an azimuthal angle of 0°, with COUGARxt having less variation than COUGAR. The configurations were also subjected to wind noise testing, where COUGARxt demonstrated superior wind noise rejection at low frequencies. The conclusion is that both configurations are suitable for outdoor acoustical measurements and that COUGARxt is the superior configuration, especially when measuring low-frequency noise.

sonic boom↗

NASA NTRSDate not supplied

Highlights from the Technical Committee on Noise

The Technical Committee on Noise (TCNS) includes researchers and industry practitioners interested in understanding noise generation from a variety of sources, its propagation, and its impact on structures, objects, and people. The goal of reducing the impact of this noise, or unwanted sound, has led to innovative model development, measurement techniques, mitigation strategies, and input towards the establishment of regulations. Community noise definition and abatement is of particular interest and motivates the advancement of research on a variety of topics, such as transportation noise from traditional and new vehicles, hearing protection, jet and rocket noise, building systems noise and vibration, atmospheric sound propagation, soundscapes, and low-frequency sound. The diverse technical background of TCNS members is essential, given the interdisciplinary nature of this research, and it is mirrored in the topics of special sessions typically held jointly with other ASA technical committees.

ASA↗