Search for dissertations about: "thesis Aerodynamic Noise"

Showing result 1 - 5 of 25 swedish dissertations containing the words thesis Aerodynamic Noise.

2. 1. Human response to wind turbine noise : perception, annoyance and moderating factors

   Author : Eja Pedersen; Sten Ljunggren; Högskolan i Halmstad; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Noise; Environmental exposure; Wind; Audio-visual interaction; Low-level noise exposure; NATURAL SCIENCES; NATURVETENSKAP; wind turbines; noise annoyance; sound perception; audio-visual interaction; low-level noise exposure;

   Abstract : Aims: The aims of this thesis were to describe and gain an understanding of how people who live in the vicinity of wind turbines are affected by wind turbine noise, and how individual, situational and visual factors, as well as sound properties, moderate the response.Methods: A cross-sectional study was carried out in a flat, mainly rural area in Sweden, with the objective to estimate the prevalence of noise annoyance and to examine the dose-response relationship between A-weighted sound pressure levels (SPLs) and perception of and annoyance with wind turbine noise. READ MORE

4. 2. On the Directivity of Railway Noise Sources

   Author : Xuetao Zhang; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; railway traction noise; railway rolling noise; line source; railway aerodynamic noise; moving source; equivalent source line; De-Dopplerization; sound emission time; sound immission time; directivity; the Doppler factor;

   Abstract : This dissertation deals with the directivity of railway noise. The directivity of railway noise is of particular importance when we have high-rise buildings close to the track, tunnel openings, partial barriers, or when we calculate the maximum sound pressure level during a pass-by based on the sound power level of the different sub-sources of a train. READ MORE

5. 3. Characterization of train-induced aerodynamic loads on high-speed railway vertical noise barriers

   Author : Dongyun Liu; Gabriel Sas; Chao Wang; Jaime Gonzalez; Lennart Elfgren; Yongming Tu; Paolo Zampieri; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aerodynamic pressure; Computational fluid dynamics; Train geometry; High-speed railway; High-speed train; Load calculation model; Vertical noise barrier; Byggkonstruktion; Structural Engineering;

   Abstract : High-Speed Railway (HSR) technology requires the deployment of noise barriers to mitigate noise pollution affecting nearby residents. As train speeds increase, so does the magnitude of aerodynamic effects such as aerodynamic noise and the pressure on these barriers, meaning that these structures require robust sound insulation and structural load-bearing capacities. READ MORE

6. 4. Aerodynamic and Aeroacoustic Analysis of a Multi-Element Airfoil using Hybrid RANS/LES Modeling Approaches

   Author : Bastian Nebenführ; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ffowcs-Williams and Hawkings; HYB0; noise; hybrid RANS LES; multi-element airfoil; CAA; Kirchhoff; Curle; high-lift;

   Abstract : Global hybrid RANS/LES simulations were used for computing the turbulent flow around a three-element airfoil. Based on the results of the flow computations, a comprehensive analysis of the flow properties was performed. READ MORE

7. 5. Applicable directivity description of railway noise sources

   Author : Xuetao Zhang; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; directivity; the Doppler factor; scattered fluid sound; railway noise; perpendicular dipole pair;

   Abstract : For a sound source, directivity is an important parameter to specify. This parameter also reflects the physical feature of the sound generation mechanism. For example, turbulence sound is of quadrupole directivity whilst fluid-structure interaction often induces a sound of dipole characteristic. READ MORE