Sökning: "grazing flow"
Visar resultat 1 - 5 av 22 avhandlingar innehållade orden grazing flow.
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. 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
4. Picophytoplankton seasonal dynamics in the Baltic Sea
Sammanfattning : Picophytoplankton (15°C there was a preference for ammonium over nitrate. Clade A/B dominated the SYN community, except during summer at the coastal station when low nitrate and warm temperatures promoted S5.2 dominance. Grazing was observed to control SYN and PPE abundances and had an effect on the SYN community structure. LÄS MER
5. 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