Sökning: "Acoustic wave absorption"
Visar resultat 1 - 5 av 8 avhandlingar innehållade orden Acoustic wave absorption.
Sammanfattning : When sound waves propagate in a duct in the presence of turbulent flow, turbulent mixing can cause attenuation of the sound waves extra to that caused by the viscothermal effects. Experiments show that compared to the viscothermal effects, this turbulent absorption becomes the dominant contribution to the sound attenuation at sufficiently low frequencies. LÄS MER
Sammanfattning : Acoustic scattering matrices are used to characterize the influence of inline duct elements on the acoustic wave propagation in wave guides.When measuring the properties of these matrices, errors are always present in the results and need to be characterized to make valid statements on the correspondence between model predictions and measurements. LÄS MER
Sammanfattning : This is a compilation thesis which investigates various mechanical phenomena in different low-dimensional nanoscale systems. In the first part, we consider a purely mechanical phenomenon: the sensitivity of the dispersion of a Love-type surface acoustic wave (SAW) to geometry and material parameters. LÄS MER
Sammanfattning : This thesis deals with physical limitations on scattering and absorption of acoustic and electromagnetic waves. A general dispersion relation for the extinction cross section of such waves is derived from the holomorphic properties of the scattering amplitude in the forward direction. LÄS MER
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