Search for dissertations about: "Linear generators"

Showing result 16 - 20 of 58 swedish dissertations containing the words Linear generators.

2. 16. Theoretical and Experimental Analysis of Operational Wave Energy Converters

   Author : Erik Lejerskog; Mats Leijon; Rafael Waters; John Ringwood; Uppsala universitet; []
   Keywords : ocean wave energy; WEC; permanent magnet; linear generator; closed stator slots; offshore experiments;

   Abstract : This thesis studies wave energy converters developed at Uppsala University. The wave energy converters are of point absorbing type with direct driven linear generators. The aim has been to study generator design with closed stator slots as well as offshore experimental studies. READ MORE

4. 17. Core Loss Prediction in Hydroelectric Generators and Analysis of a Contra-Rotating Machine Topology

   Author : Martin Ranlöf; Uppsala universitet; []
   Keywords : TECHNOLOGY; TEKNIKVETENSKAP;

   Abstract : The call for increased accuracy in the process of design and analysis of electrical machines has encouraged the use of numerical methods to calculate the electric and magnetic field distributions within this type of apparatus. The finite element method is a numerical technique that has become specifically widespread and popular, due to the relative swiftness and accuracy with which it is possible to treat complex machine geometries and non-linear material characteristics. READ MORE

5. 18. Lefschetz Properties of Monomial Ideals

   Author : Nasrin Altafi; Mats Boij; Alicia Dickenstein; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Weak Lefschetz property; monomial ideals; group actions; almost linear resolution; Mathematics; Matematik;

   Abstract : This thesis concerns the study of the Lefschetz properties of artinian monomial algebras. An artinian algebra is said to satisfy the strong Lefschetz property if multiplication by all powers of a general linear form has maximal rank in every degree. If it holds for the first power it is said to have the weak Lefschetz property (WLP). READ MORE

6. 19. Attenuation of boundary layer disturbances by means of streamwise vortices

   Author : Sohrab Sattarzadeh Shirvan; Jens H. M. Fransson; Valery Chernoray; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer stability; Tollmien-Schlichting waves; oblique waves; transition to turbulence; streamwise vortices; miniature vortex generators; instability control; drag reduction;

   Abstract : The stability of the boundary layer developed on a flat plate is studied in the presence of streamwise streaks where disturbances of different types are introduced in the wall-bounded shear layer. The experimental investigations are aimed at flow control by means of passively damping the energy growth of the disturbances in the streaky boundary layer and furthermore delay the onset of the transition in the streamwise direction. READ MORE

7. 20. Boundary layer streaks as a novel laminar flow control method

   Author : Sohrab Sattarzadeh Shirvan; Jens H. M. Fransson; Edward B. White; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer stability; laminar to turbulent transition; laminar flow control; drag reduction; Tollmien-Schlichting waves; oblique waves; streaky boundary layers; miniature vortex generators; discrete suction;

   Abstract : A novel laminar flow control based on generation of spanwise mean velocity gradients (SVG) in a flat plate boundary layer is investigated where disturbances of different types are introduced in the wall-bounded shear layer. The experimental investigations are aimed at; (i) generating stable and steady streamwise streaks in the boundary layer which set up spanwise gradients in the mean flow, and (ii) attenuating disturbance energy growth in the streaky boundary layers and hence delaying the onset of turbulence transition. READ MORE