Sökning: "Acoustic liner"
Visar resultat 1 - 5 av 9 avhandlingar innehållade orden Acoustic liner.
1. Analysis of Acoustic Absorption with Extended Liner Reaction and Grazing Flow
Sammanfattning : Acoustic absorbing liners are efficient and commonly used measures to reduce sound levels in many fields of application. The sound reducingperformance of the liners is dependent on the acoustic state, defined by e.g. the flow and sound field interacting with the liner. LÄS MER
2. Acoustic characterization of orifices and perforated liners with flow and high-level acoustic excitation
Sammanfattning : This thesis is motivated by the need for noise control in aircraft engine with orifices and perforated liner. The presence of high-level acoustic excitation, different flow situations either bias flow, grazing flow or any combination in the aircraft engine, makes the acoustic behavior complex due to the interaction between sound and flow over the lined wall. LÄS MER
3. Large Eddy Simulation for the Analysis of Jet Noise Suppression Devices
Sammanfattning : Stricter noise regulations for commercial aircraft have increased interest in noise reduction techniques within the aerospace industry. To meet the requirements new noise suppression technologies have to be delveoped and the numerical methods need to be validated and possibly improved for the correct assessment of these new technologies. LÄS MER
4. Numerical Simulations of Noise Reduction Devices for Aero Engines
Sammanfattning : Increasing air traffic and denser population around airports have led to stricterregulations on aircraft noise. The engine is the main source of noise of jet aircraft.Decreasing jet engine noise can in some cases reduce sonic fatigue andthereby increase the engine lifetime. LÄS MER
5. Large Eddy Simulation for the Analysis of Supersonic Jet Noise Suppression Devices
Sammanfattning : Stricter noise regulations for commercial and military aircraft have increased interest in noise reduction techniques within the aerospace industry. To meet the requirements, new noise suppression technologies have to be developed and numerical methods need to be validated and possibly improved for the correct assessment of these technologies. LÄS MER