Sökning: "Ffowcs-Williams and Hawkings"

Visar resultat 6 - 10 av 11 avhandlingar innehållade orden Ffowcs-Williams and Hawkings.

1. 6. Numerical Methods for Aeroacoustic Analysis of Turbomachines

   Författare :Daniel Lindblad; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Stability Analysis; Acoustic Analogy; Tonal Noise; Nonreflecting Boundary Conditions; Duct Modes; Turbomachinery; Harmonic Balance; Ffowcs Williams - Hawkings; Time Sampling; Aliasing;

   Sammanfattning : Numerical simulations are important tools for developing new aircraft that can meet future needs. When numerical simulations are used to compute aircraft noise, a two-step procedure is often employed. In the first step, the noise sources are determined using, e.g. LÄS MER

3. 7. Numerical Methods for Aeroacoustic Analysis of Turbomachinery

   Författare :Daniel Lindblad; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Convective Ffowcs Williams - Hawkings Equation; Computational Aeroacoustics; Acoustic Analogy; Von Neumann Stability Analysis; Tonal Noise; CAA; Harmonic Balance Method; Counter Rotating Open Rotor;

   Sammanfattning : Air transportation is today an integral part of many peoples life and it continuously grow to serve more of us in new and ingenious ways. There are however negative sides to this growth as well, such as increased noise around airports and more CO2 emissions, which must be addressed if aviation is to be part of a sustainable future. LÄS MER

4. 8. An experimental and numerical study of an automotive cooling module

   Författare :Anders Rynell; Gunilla Efraimsson; Michael Shur; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fan installation effects; spectral decomposition; aeroacoustics; Vehicle and Maritime Engineering; Farkostteknik;

   Sammanfattning : Heavy vehicles are major emitters of noise. Especially at idle or low vehicle speeds a large portion of the noise emanates from the fan that forces the flow through the cooling module. The aim of this work is to investigate and reveal aerodynamic and acoustic installation effects linked to the cooling package. LÄS MER

5. 9. Numerical prediction of propeller induced hull pressure pulses and noise

   Författare :Muye Ge; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; RANS; Transition; IDDES; Cavitation; Pressure pulses; Sheet cavitation inception; Ship noise; k − ω SST; FWH acoustic analogy; Hydroacoustics;

   Sammanfattning : An operating marine propeller is one of the major sources inducing hull pressure pulses, onboard noise and vibration as well as underwater radiated noise. There are rising concerns of environmental impacts and comfort and welfare of passengers and crews due to these negative effects. LÄS MER

7. 10. Numerical Simulations of Turbulent Flows at Widely Different Mach Numbers

   Författare :Dragos Moroianu; Strömningsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; vibration and acoustic engineering; Maskinteknik; hydraulics; vacuum technology; Mechanical engineering; plasma; Energy research; Energiforskning; fluiddynamik; plasmas; Gaser; fluid dynamics; Gases; computational fluid dynamics; Acoustic; hydraulik; vakuumteknik; vibrationer; akustik; compressible flow;

   Sammanfattning : The present thesis mainly focuses on the numerical simulation of the turbulent flow field and acoustics developed in different industrial applications. The study covers a large range of Mach numbers, starting from incompressible regimes and ending with a fully compressible flow. LÄS MER