Aeroacoustic Measurements by Thomas J. Mueller, Christopher S. Allen, William K. Blake,

By Thomas J. Mueller, Christopher S. Allen, William K. Blake, Robert P. Dougherty, Denis Lynch, Paul T. Soderman, James R. Underbrink

The aim of aeroacoustic measurements is to supply a foundation for assessing mechanisms of noise iteration, and to boost tools of lowering noise to extra appropriate degrees. in spite of the fact that, the measurements themselves are complicated, and require a deep knowing of the experimental facility applied (such as a wind tunnel), dimension instrumentation, and information research options.
In this quantity fresh advances within the size and realizing of aerodynamically generated sound are provided by means of leaders within the improvement of recent options during this box. either uncomplicated and utilized difficulties are coated in detail.

Show description

Read Online or Download Aeroacoustic Measurements PDF

Best measurements books

Parametric x ray radiation in crystals theory experiments and applications

This systematic and finished monograph is dedicated to parametric X-ray radiation (PXR). This radiation is generated by way of the movement of electrons within a crystal, wherein the emitted photons are diffracted by way of the crystal and the radiation depth significantly dependsĀ on the parameters of the crystal constitution.

Multisensor Instrumentation 6 Design: Defined Accuracy Computer Integrated Measurement Systems

A groundbreaking booklet in accordance with a landmark caliber initiativeIn modern-day information-driven corporations, accuracy is key in computer-integrated dimension and keep watch over structures, the place academia, executive, and make investments enormous assets in methodologies for reaching and preserving excessive functionality.

501 measurement and conversion questions

This publication serves readers who are looking to increase the dimension and conversion talents they should be triumphant in school and on assessments. the 10 sections of this booklet make sure that readers perform a number of questions together with perimeter, quarter, quantity, and angles. With over 500 perform questions, this booklet is an important device for college kids who have to increase their math talents to move tests very easily.

Extra info for Aeroacoustic Measurements

Sample text

They found that for the frequencies below 30 kHz, the effect of turbulence absorption was not important. 5 The wave convection of intensity is not the same as acoustic pressure convective amplification discussed with Eq. 24). Intensity is the acoustic energy that flows through a unit area in unit time and, in still air, is equal to the time average product of acoustic pressure and particle velocity. However, in a moving stream, a fixed noise source will experience a convective amplification of the pressure and velocity terms.

100 1000 frequency, 1f3 octave bands, Hz ~~ 10000 Fig. 15. 40 x 80 background noise at 445 km/h before and after modification of the test section acoustic lining (Soderman et al. 2000) Open-Jet Background Noise In addition to drive-fan and wind noise, an in-airstream microphone in an open-jet wind tunnel is also exposed to sound from the shear layers - particularly as the shear layers induce unsteady pressures on the nozzle and collector. That is mitigated to some extent by the lack of test section walls, which eliminates wall boundary-layer noise and allows drive-fan sound waves to propagate into the open room.

2000) Background Noise from Wall Boundary Layer Depending on wind tunnel wall roughness and distance from strut-mounted microphones, wall boundary layers can be a source of background noise. Between roughly 5 kHz and 12 kHz, the 40 X 80-background noise was dominated by noise from the test section wall boundary layer before steps were taken to smooth the surface. 15 measured before and after installation of a new test section lining (Soderman et al. 2000). Prior to the modification, a 152-mm deep sound absorbent lining with a 40 %-open perforated metal face sheet covered the walls.

Download PDF sample

Rated 4.30 of 5 – based on 26 votes

Author: admin