Sökning: "Acoustic Impedance"
Visar resultat 1 - 5 av 49 avhandlingar innehållade orden Acoustic Impedance.
1. 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
2. Acoustic Forces in Cytometry and Biomedical Applications: Multidimensional Acoustophoresis
Sammanfattning : Over the last decades the ongoing work in the fields of Lab-on-a-Chip and Micro-Total-Analysis-Systems has led to the discovery of new or improved ways to handle and analyse small volumes of biofluids and complex biosuspensions. The benefits of working on the microscale include: miniaturization of the analysis systems with less need for large sample volumes; temporal and spatial control of suspended particle/cell positions; low volume sheath flow lamination or mixing; novel separation techniques by using forces inherent to the microscale domain; precise regulation of sample temperatures and rapid analysis with less volumes needed to be processed. LÄS MER
3. Experimental Investigation of the Acoustic Properties of Perforate using Acoustic Three-Ports
Sammanfattning : This thesis discusses the aero-acoustic characterisation of a perforate sample using a three-port technique. A rectangular T-junction with a flush mounted perforated sample at the intersection form the acoustical three-port. LÄS MER
4. Innovative noise control in ducts
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
5. Assessing precision and accuracy in acoustic scattering matrix measurements
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