Sökning: "Teknisk akustik"

Visar resultat 6 - 10 av 213 avhandlingar innehållade orden Teknisk akustik.

1. 6. Numerical Modelling of Dynamics of Light Porous Materials

   Författare :Peter Göransson; Teknisk akustik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mechanical engineering; glass fibre; foam; material characterisation; elasto-acoustic; fluid-structure interaction; finite element; Biot; porous material; hydraulics; vacuum technology; vibration and acoustic engineering; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik;

   Sammanfattning : Porous materials are among the most commonly used materials for noise and vibration reduction in modern transportation vehicles. To design, industrially relevant, weight and cost effective noise and vibration measures, there is a need for general prediction models capable of representing the elasto-acoustic behaviour of such materials. LÄS MER

3. 7. Turbulent flows over permissive boundaries and porous walls

   Författare :Seyed Morteza Habibi Khorasani; Shervin Bagheri; Geert Brethouwer; Alfredo Soldati; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct numerical simulations; wall-bounded turbulence; flow control; porous walls; heat transfer; Direkta numeriska simuleringar; väggbunden turbulens; flödeskontroll; porösa väggar; värmeöverföring; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : This thesis investigates how in wall-bounded turbulent flows changes to the wall can induce changes in the flow. To this end, we investigate the use of wall boundary conditions meant to mimic the effect of textured surfaces. LÄS MER

4. 8. Acoustical properties of earplugs

   Författare :Per Hiselius; Teknisk akustik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik; vibration and acoustic engineering; vacuum technology; hydraulics; Mechanical engineering; acoustic modelling; objective measurement; insertion loss; earplugs; HPE; HPD; hearing protectors; Two-Port; Four-Pole; attenuation; electro acoustics; acoustics;

   Sammanfattning : In this study an experimental setup for measurements of high impedance objects in ducts, yielding the acoustical Two-Port properties of the object, is applied to earplugs. A frequently used experimental setup for measuring objective acoustical properties of earplugs is that of artificial ears. Great effort is spent on duplicating the human ear. LÄS MER

5. 9. Drum sound from floor coverings - objective and subjective assessment

   Författare :Ann-Charlotte Johansson; Teknisk akustik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; vakuumteknik; vibrationer; akustik; hydraulik; Maskinteknik; vacuum technology; vibration and acoustic engineering; hydraulics; acoustic standard; Mechanical engineering; tapping machine; veneer flooring; parquet flooring; binaural recording; foot impact; loudness; sound quality; listening test; paired comparisons; walking sound; drum sound; building acoustics; psychoacoustics; laminate flooring;

   Sammanfattning : Drum sound is the sound produced when an object, such as a foot, hits the flooring in the room in which the receiving ear is located. Drum sound has attracted interest in recent years, particularly due to an increased use of thin floating floor constructions, such as veneer or laminate flooring, which can produce loud and sharp walking sound. LÄS MER

7. 10. On stability of vortices and vorticity generated by actuator lines

   Författare :Vitor Gabriel Kleine; Dan S. Henningson; Ardeshir Hanifi; Stéphane Le Dizès; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : Vortices are present in nature and in many flows of industrial importance. The stability of configurations of vortices can have real-world consequences, because vortices play a crucial role in accelerated mixing. In particular, vortices are present in the wake of wind turbines and other rotors. LÄS MER