Sökning: "flow noise"

Visar resultat 1 - 5 av 208 avhandlingar innehållade orden flow noise.

1. 1. Predicting flow-generated noise from HVAC components

   Författare :Oscar Kårekull; Mats Åbom; Gunilla Efraimsson; Joachim Golliard; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow noise; noise prediction; HVAC; flödesalstrat ljud; bullerprediktion; HVAC;

   Sammanfattning : More energy efficient fans, i.e. larger sizes running at lower speeds, in Heating Ventilation and Air Conditioning (HVAC) systems decrease the fan noise and increase the importance of flow generated noise in other system components, e.g. LÄS MER

3. 2. Modelling of low frequency sound in duct networks

   Författare :Stefan Nygård; KTH; []
   Nyckelord :Duct pipe; System network; Wave-guide; Flow; Sound; Noise; Fluid machine; 2-port; 1-port; Active; Passive; Flow separation; Code; Simulation; Low frequency;

   Sammanfattning : .... LÄS MER

4. 3. Modelling of IC-Engine Intake Noise

   Författare :Magnus Knutsson; Mats Åbom; Yves Auregán; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; IC-engine; intake noise; gas dynamics; linear source data; frequency domain; 2-port; losses; air cleaner unit; filter paper; flow; FEM; BEM; charge air cooler; narrow tube; Acoustics; Akustik;

   Sammanfattning : Shorter product development cycles, densely packed engine compartments and intensified noiselegislation increase the need for accurate predictions of IC-engine air intake noise at earlystages. The urgent focus on the increasing CO2 emissions and the efficiency of IC-engines, aswell as new techniques such as homogeneous charge compression ignition (HCCI) mightworsen the noise situation. LÄS MER

5. 4. Innovative noise control in ducts

   Författare :Maaz Farooqui; Mats Åbom; Hans Bodén; Tamer Elnady; Jeong-Guon Ih; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Locally resonant materials; slow sound; acoustic impedance; metallic foam; low frequency noise; mufflers; lined ducts; grazing flow; flow duct; impedance eduction.; Vehicle and Maritime Engineering; Farkostteknik;

   Sammanfattning : The objective of this doctoral thesis is to study three different innovative noise control techniques in ducts namely: acoustic metamaterials, porous absorbers and microperforates. There has been a lot of research done on all these three topics in the context of duct acoustics. LÄS MER

7. 5. Prediction and Optimisation of Traffic Noise. A Study on Noise Barriers and Shielded Areas

   Författare :Pontus Thorsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; city canyon; absorption; city noise; insertion loss; traffic noise; soundscape; silent side; noise barrier; ground impedance;

   Sammanfattning : The main contribution of noise levels in cities is today road traffic. The strongest source for all road vehicles is most often the tyre-road contact. This source position close to the ground is fortunate with respect to secondary noise abatement measures, such as absorbing road surfaces or noise barriers. LÄS MER