Sökning: "Susann Boij"
Visar resultat 1 - 5 av 12 avhandlingar innehållade orden Susann Boij.
Sammanfattning : The subject of this thesis is the acoustic properties offlow duct area expansions and the influence of flow-acousticcoupling at sharp edges. For low Mach number flow, significantinteraction between the sound field and the flow field canoccur at such points of flow separation. LÄS MER
Sammanfattning : Environmental noise has for decades been a well known problem, especially in urban areas. As noise requirements for vehicles are sharpened, noise reducing concepts are needed in early design stages requiring accurate simulations to support the design. LÄS MER
Sammanfattning : Noise is a major environmental pollutant, which can inict physical and psychologicalinjury. An important noise contribution stems from aeroacousticsources, which are found in e.g., ventilation ducts, engine exhaust systems andairplane engines. LÄS MER
Sammanfattning : Aeroengine noise is one of the dominating noise sources in today’s aircraft. Reduction of the aeroengine noise is related to multiphysics phenomena, and that is subject to different mechanisms, e.g., the coupling between turbulence, flame and sound waves. LÄS MER
5. Frequency Domain Linearized Navier-Stokes Equations Methodology for Aero-Acoustic and Thermoacoustic Simulations
Sammanfattning : The first part of the thesis focuses on developing a numerical methodology to simulate the acoustic properties of a hybrid liner consisting of a perforated plate, a porous layer and a Helmholtz cavity. Liners are always a standard way to reduce noise in today’s aeroengines, e.g. LÄS MER