Search for dissertations about: "Aeroacoustics"

Showing result 6 - 10 of 26 swedish dissertations containing the word Aeroacoustics.

2. 6. Centrifugal compressor flow instabilities at low mass flow rate

   Author : Elias Sundström; Mihai Mihaescu; Håkan Nilsson; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Centrifugal Compressor; Large Eddy Simulation; Internal Com- bustion Engine; Aeroacoustics; Modal Flow Decomposition;

   Abstract : Turbochargers play an important role in increasing the energetic efficiency andreducing emissions of modern power-train systems based on downsized recipro-cating internal combustion engines (ICE). The centrifugal compressor in tur-bochargers is limited at off-design operating conditions by the inception of flowinstabilities causing rotating stall and surge. READ MORE

4. 7. Advanced Fluid-Structure Interaction Modelling and Simulation for Aerospace Applications

   Author : Stefan Nilsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aeroacoustics; Hybrid RANS-LES; CSD; cavity flow; aeroelastics; CFD; FSI;

   Abstract : Numerical fluid-structure interaction (FSI) methods for the prediction of aeroelastic phenomena are important within aerospace. The continuous development of computer technologies has enabled the use of more advanced FSI methods. The use of advanced methods has the potential to provide more accurate predictions. READ MORE

5. 8. A Study of Subsonic Turbulent Jets and Their Radiated Sound Using Large-Eddy Simulation

   Author : Niklas Andersson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Two-Point Space-Time Correlations; CAA; Jet Noise; LES; Kirchhoff; Coaxial Jets; Heated Jets; Aeroacoustics;

   Abstract : Stricter noise regulation for near-ground operations has made noise reduction in commercial aircraft a topic of growing interest in the aerospace industry. To meet airworthiness requirements new noise reduction technologies have to be developed and numerical methods for correct assessment of these technologies are desirable. READ MORE

6. 9. Computational Aeroacoustics Based on Large Eddy Simulation and Acoustic Analogies

   Author : Mihai Mihaescu; Laszlo Fuchs; Strömningsteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mechanical engineering; hydraulics; plasma; Technological sciences; Teknik; fluiddynamik; plasmas; Gaser; fluid dynamics; Gases; Inhomogeneous Wave Equation; Acoustic Boundary Conditions; Acoustic Source Terms; LES; Computational Aeroacoustics; Turbulent Flows; vacuum technology; vibration and acoustic engineering; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik; Computational Aeroacoustics;

   Abstract : The thesis presents a numerical method developed by the author and its applications for computing the generated sound by an unsteady flow field and its propagation. The full equations of motion for compressible and unsteady flows describe both flow field and sound generation and propagation. READ MORE

7. 10. Turbulence-resolving simulations for engineering applications

   Author : Bastian Nebenführ; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LES; Aeroacoustics; Forest canopy; Airframe noise; hybrid RANS LES; Turbulence-resolving simulation; Wind-turbine fatigue loads; Wind power;

   Abstract : Most fluid flows of industrial interest are turbulent and their accurate representation may be of vital importance for the design process of new products. To date, steady RANS methods are usually employed for the simulation of turbulent flows of everyday engineering problems. READ MORE