Searched for: subject:"aeroacoustics"
(1 - 20 of 21)

Pages

document
Malgoezar, A.M.N. (author)
Humans localize sound incessantly using the ears and it proves to be important of<br/>our awareness. It can also be a cause of annoyance to the community whenever<br/>sound is in the form of noise. Due to increase of wealth, industry, technology and<br/>corresponding globalization there is a large increase of noise. Especially with the<br/...
doctoral thesis 2019
document
Kurelek, J.W. (author), Kotsonis, M. (author), Yarusevych, S. (author)
Transition and flow development in a separation bubble formed on an airfoil are studied experimentally. The effects of tonal and broadband acoustic excitation are considered since such acoustic emissions commonly result from airfoil self-noise and can influence flow development via a feedback loop. This interdependence is decoupled, and the...
journal article 2018
document
Avallone, F. (author), van der Velden, W.C.P. (author), Ragni, D. (author), Casalino, D. (author)
Trailing-edge serrations are add ons retrofitted to wind-turbine blades to mitigate turbulent boundary-layer trailing-edge noise. This manuscript studies the physical mechanisms behind the noise reduction by investigating the far-field noise and the hydrodynamic flow field. A conventional sawtooth and a combed-sawtooth trailing-edge serration...
journal article 2018
document
Avallone, F. (author), van der Velden, W.C.P. (author), Ragni, D. (author)
Far-field noise and flow field over a novel curved trailing-edge serration (named as iron-shaped serration) are investigated. Spectra of the far-field broadband noise, directivity plots and the flow-field over the iron-shaped serration are obtained from numerical computations performed using a compressible Lattice-Boltzmann solver. The new...
journal article 2017
document
Ragni, D. (author), Avallone, F. (author), van der Velden, W.C.P. (author)
The far-field noise and flow field of a novel curved trailing-edge serration (i.e. iron-shaped) are investigated. Spectra of the far-field broadband noise, directivity plots and the flow-field over the iron-shaped serration are obtained from numerical computations performed using a compressible Lattice-Boltzmann solver. The new design is...
conference paper 2017
document
Pröbsting, S. (author)
Noise generated aerodynamically by the airflow over a lifting surface is often of concern for applications as diverse as air and ground transportation, heating, ventilation, air-conditioning systems, and wind turbines. The thesis describes the application of advanced optical flow measurements techniques for the visualization and description of...
doctoral thesis 2015
document
Pröbsting, S. (author), Serpieri, J. (author), Scarano, F. (author)
The present study investigates the mechanisms associated with tonal noise emission from a NACA 0012 aerofoil at moderate incidence (0; 1; 2 and 4 angle of attack) and with Reynolds numbers ranging from 100 000 to 270 000. Simultaneous time-resolved particle image velocimetry (PIV) of the aeroacoustic source region near the trailing edge and...
journal article 2014
document
Violato, D. (author), Scarano, F. (author)
The three-dimensional behavior of jet core breakdown is investigated with experiments conducted on a free water jet at Re = 5000 by time-resolved tomographic particle image velocimetry (TR-TOMO PIV). The investigated domain encompasses the range between 0 and 10 jet diameters. The characteristic pulsatile motion of vortex ring shedding and...
journal article 2013
document
De Jong, A.T. (author)
doctoral thesis 2012
document
Lorenzoni, V. (author), Ragni, D. (author)
An experimental study of the flow inside a saxophone mouthpiece in playing conditions is carried out by means of particle image velocimetry at high acquisition rate. Planar velocity measurements on the midsection of a Plexiglas tenor saxophone mouthpiece are performed, respectively, in the mouthpiece baffle and in the reed channel. Sequences of...
journal article 2012
document
Violato, D. (author), Scarano, F. (author)
The three-dimensional behavior of flow transition in circular and 6-chevron jets at Re?=?5000 is investigated with experiments conducted on a free water jet by time-resolved tomographic particle image velocimetry. The emphasis is on the unsteady organization of coherent flow structures, which play a role in the generation of acoustic noise....
journal article 2011
document
Koschatzky, V. (author)
This thesis deals with the problem of noise. Sound is a constant presence in our lives. Most of the times it is something wanted and it serves a purpose, such as communication through speech or entertainment by listening to music. On the other hand, quite often sound is an annoying and unwanted by-product of some other activity necessary to us....
doctoral thesis 2011
document
Koschatzky, V. (author), Westerweel, J. (author), Boersma, B.J. (author)
The aim of the present study is to compare two different acoustic analogies applied to time-resolved particle image velocimetry (PIV) data for the prediction of the acoustic far-field generated by the flow over a rectangular cavity. We consider the model problem of sound radiating from an open, two-dimensional, shallow cavity with an aspect...
journal article 2011
document
De Jong, A.T. (author), Bijl, H. (author)
Cavity aeroacoustic noise is relevant for aerospace and automotive industries and widely investigated since the 1950s. Most investigations so far consider cavities where opening length and width are of similar scale. The present investigation focuses on a less investigated setup, namely cavities that resemble the door gaps of automobiles. These...
journal article 2010
document
Moore, P.D. (author)
Jet noise is an extensively studied phenomenon since the deployment of the first civil jet aircraft more than 50 years ago. Jet noise makes up a considerable portion of the total noise of jet aircraft, and the expansion of the numbers of airplanes and airports has only been possible by keeping the noise of airplanes under control. However, while...
doctoral thesis 2009
document
Testa, C. (author)
doctoral thesis 2008
document
Arina, R. (author), Ceresola, N. (author)
A numerical simulation of the turbulent flow field of a transonic cavity and its associated far-field sound radiation, are presented. The test case is based on the experimental case M219 of QinetiQ. Two different turbulent simulations are performed, the first one is a URANS simulation with a k-w-EARSM turbulence model. while a DES turbulence...
conference paper 2006
document
Utzmann, J. (author), Munz, C.D. (author)
This paper advances the idea of a heterogeneous domain decomposition for Computational Aeroacoustics (CAA). Direct simulations of aeroacoustic problems are accelerated by sub-dividing the computational domain into smaller domains. In each of these sub-domains the equations, the discretization, the mesh and the time step may be different and are...
conference paper 2006
document
Lörcher, F. (author), Gassner, G. (author), Munz, C.D. (author)
Numerical schemes for wave propagation over long distances need good wave propagation properties with low dispersion and low dissipation errors. Suitable numerical methods are methods with high order of accuracy in space and time. For space discretization on structured grids, high order finite difference schemes are efficient, and, if a...
conference paper 2006
document
Taghaddosi, F. (author), Habashi, W.G. (author)
A three-dimensional computational aeroacoustics code has been developed for the simulation of tone noise generated by turbofan engine inlets. The code is based on the linearized Euler equations, rewritten in terms of acoustic potential and solved in the frequency domain. Spatial discretization is performed using a spectral element method....
conference paper 2006
Searched for: subject:"aeroacoustics"
(1 - 20 of 21)

Pages