Search for dissertations about: "wind.tunnels"

Showing result 6 - 10 of 14 swedish dissertations containing the word wind.tunnels.

2. 6. Aerodynamic Studies of Vertical Axis Wind Turbines using the Actuator Line Model

   Author : Victor Mendoza; Anders Goude; Hans Bernhoff; Robert Flemming Mikkelsen; Uppsala universitet; []
   Keywords : wind power; vertical axis wind turbines VAWTs ; actuator line model ALM ; dynamic stall model DSM ; atmospheric boundary layer ABL ; wake deflection; atmospheric boundary layer ABL ; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

   Abstract : This thesis addresses the unsteady aerodynamics involved in the operation of vertical axis wind turbines (VAWTs). The main focus is to represent and understand the most relevant phenomena within the resulting flow pattern as the wake structure, loads on the different turbine components and the performance of the rotor. READ MORE

4. 7. Wind-turbine wake flows - Effects of boundary layers and periodic disturbances

   Author : Ylva Odemark; Jens Fransson; Per-Åge Krogstad; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wind power; wind-turbine model; wind tunnel; porous disc; hot-wire anemometry; particle image velocimetry; blade element momentum method; large eddy simulations; actuator disc method;

   Abstract : The increased fatigue loads and decreased power output of a wind turbine placed in the wake of another turbine is a well-known problem when building new wind-power farms and a subject of intensive research. These problems are caused by the velocity gradients and high turbulence levels present in the wake of a turbine. READ MORE

5. 8. Effects of free-stream turbulence and three-dimensional roughness on boundary layer transition

   Author : Santhosh Babu Mamidala; Jens H. M. Fransson; Bengt E. G. Fallenius; Jonathan Morrison; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary-layer transition; intermittency; free-stream turbulence; electret microphones; isolated roughness; sinuous instability; varicose instability; Engineering Mechanics; Teknisk mekanik;

   Abstract : External disturbances such as free-stream turbulence (FST), and isolated three-dimensional roughness are strong disturbance sources to the laminar boundary layers (BLs), which can lead to a rapid transition to turbulence. The transition process eventuates to increase in skin-friction coefficient and heat transfer rate and hence, both of the aforementioned disturbance sources have practical importance. READ MORE

6. 9. The Aerodynamic Correlation of a Scale Model with a Full Size Car

   Author : Lasse Malmkjaer Christoffersen; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Cooling flow.; Correlation; Experiment; Reynolds number; Road Vehicle Aerodynamics; CFD; Scale model;

   Abstract : Reducing the Worlds consumption of energy has become an important part of the current political and environmental debate. The reasons are obvious: World population is increasing, continued growth in living standards, finite availability of resources and finally green house gas emissions from energy production have to be brought down to stabilize temperatures. READ MORE

7. 10. Vehicle wakes in side wind

   Author : Magnus Urquhart; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; surrogate model; optimization; CFD; wind; crossflow; drag; yaw; cavity; wake; tomographic PIV; aerodynamics;

   Abstract : There is a global push to reduce the energy consumption of passenger vehicles with increasingly stringent targets and regulations. More than one-tenth of Europe's greenhouse gasses are due to passenger vehicles. The aerodynamic drag is a major contributor to energy consumption responsible for more than a quarter of the vehicle's energy usage. READ MORE