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Visar resultat 6 - 10 av 1066 avhandlingar som matchar ovanstående sökkriterier.

1. 6. A Novel Signal Model and Estimation Method for Acoustic Doppler Current Meters

   Författare :Thomas L Lagö; Teknisk akustik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Doppler Profiler; Acoustic Doppler; Gaussian Backscattering Model; ADCM; ADCP; The Symmiktos Method; Estimation; Doppler; Current; MPCA.; Technological sciences; Teknik; Electromagnetism; optics; acoustics; Elektromagnetism; optik; akustik;

   Sammanfattning : This thesis deals with the process of estimating underwater current from the backscattering signal transmitted from an ultrasonic transducer. The narrowband sinusoidal burst signal is Doppler-shifted due to the current, and this information is converted into current. LÄS MER

3. 7. Applications of the Complex Modulation Transfer Function on SEA-systems

   Författare :Karl-Ola Lundberg; Teknisk akustik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; vacuum technology; hydraulics; Mechanical engineering; modulated noise; in-situ; modulation transfer function; loss factor; SEA; vibration and acoustic engineering; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik;

   Sammanfattning : The SEA coupling and dissipation loss factors are determined in-situ from Complex Modulation Transfer Functions, CMTF:s, based on measured impulse-responses. A quotient of CMTF:s is least-square curve-fitted to a SEA model and the SEA loss factors are determined from the results of the curve-fit. LÄS MER

4. 8. CFD of Duct Acoustics for Turbocharger Applications

   Författare :Emma Alenius; Mats Åbom; Laszlo Fuchs; Federico Piscaglia; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aero acoustics; Large Eddy Simulation; IC-engines; 1D models; turbocharger; orifice plate; Acoustics; Akustik; Fluid mechanics; Strömningsmekanik;

   Sammanfattning : The search for quieter internal combustion engines drives the quest for a better understanding of the acoustic properties of engine duct components. In this work the main focus is the turbocharger compressor and a discussion of turbocharger acoustics and earlier work within the area is presented, giving an insight into its sound generating mechanisms and the damping effect it has on pressure pulses, i. LÄS MER

5. 9. Numerical study of flows related to aerated stirred tanks

   Författare :Dragana Arlov; Strömningsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; plasma; fluiddynamik; Gaser; plasmas; fluid dynamics; Gases; Lattice Boltzmann method; Volume of Fluid; Aerated stirred tank; Large Eddy Simulation; Eulerian-Lagrangian model; Energy research; Energiforskning; Mechanical engineering; hydraulics; vacuum technology; vibration and acoustic engineering; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik;

   Sammanfattning : The overall purpose with this work is to investigate the bubbly flow in a aerated stirred tank using numerical simulations. Aerated stirred tanks are commonly used in chemical processes for producing for example insulin and antibiotics. LÄS MER

7. 10. Vibration of sandwich beams

   Författare :Daniel Backström; Anders Nilsson; Goran Pavic; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Acoustics; Akustik;

   Sammanfattning : Some aspects and properties of the lateral vibration of sandwich beams are investigated, including the concept of apparent bending stiffness and shear modulus, allowing the sandwich beam dynamics to be approximately described by classical beam theory. A sixth order beam model is derived including boundary conditions, and the free and forced response of some beam configurations analyzed. LÄS MER