Sökning: "focused waves"

Visar resultat 1 - 5 av 57 avhandlingar innehållade orden focused waves.

  1. 1. Extreme wave conditions and the impact on wave energy converters

    Författare :Eirini Katsidoniotaki; Malin Göteman; Vincent Neary; Uppsala universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; extreme waves; wave energy converters; CFD; OpenFOAM; environmental contours; focused waves; breaking waves;

    Sammanfattning : The amount of energy enclosed in ocean waves has been classified as one of the most promising renewable energy sources. Nowadays, different wave energy conversion (WEC) systems are being investigated, but only a few concepts have been operated in a sea environment. LÄS MER

  2. 2. Interaction between Electromagnetic Waves and Localized Plasma Oscillations

    Författare :Jan-Ove Hall; Thomas Leyser; Jan Trulsen; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; space physics; plasma physics; radio waves; ionospheric modification; density depleations; field-aligned irregularities; lower hybrid solitary structures; lower hybrid cavities; Z mode waves; magnetosonic waves; scattering; mode conversion; Rymd- och plasmafysik; Space physics; Rymdfysik;

    Sammanfattning : This thesis treats interaction between electromagnetic waves and localized plasma oscillations. Two specific physical systems are considered, namely artificially excited magnetic field-aligned irregularities (striations) and naturally excited lower hybrid solitary structures (LHSS). LÄS MER

  3. 3. Air-coupled microphone measurements of guided waves in concrete plates

    Författare :Henrik Bjurström; Nils Rydén; Björn Birgisson; Tadeusz Stepinski; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Non-destructive testing; Lamb waves; surface waves; air-coupled microphones; non-contact measurements;

    Sammanfattning : Quality control and quality assurance of pavements is today primarily based on core samples. Air void content and pavement thickness are parameters that are evaluated. However, no parameter connected to the stiffness is evaluated. LÄS MER

  4. 4. On dynamics and thermal radiation of imploding shock waves

    Författare :Malte Kjellander; Nicholas Apazidis; Gabi Ben-Dor; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; converging shock waves; polygonal shock waves; temperature measurments; argon; plasma creation; ionisation; spectrometry; Engineering mechanics; Teknisk mekanik;

    Sammanfattning : Converging cylindrical shock waves have been studied experimentally. Numericalcalculations based on the Euler equations and analytical comparisons basedon the approximate theory of geometrical shock dynamics have been made tocomplement the study.Shock waves with circular or polygonal shock front shapes have been createdand focused in a shock tube. LÄS MER

  5. 5. Alfvén Waves and Energy Transformation in Space Plasmas

    Författare :Yuri Khotyaintsev; Kalevi Mursula; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; Alfvén waves; particle acceleration; ionosphere; magnetopause; magnetic reconnection; Rymd- och plasmafysik; Space physics; Rymdfysik; Space Physics; rymdfysik;

    Sammanfattning : This thesis is focused on the role of Alfvén waves in the energy transformation and transport in the magnetosphere. Different aspects of Alfvén wave generation, propagation and dissipation are considered. The study involves analysis of experimental data from the Freja, Polar and Cluster spacecraft, as well as theoretical development. LÄS MER