Sökning: "Wake Analysis Method"

Visar resultat 1 - 5 av 36 avhandlingar innehållade orden Wake Analysis Method.

1. 1. Numerical computations of wind turbine wakes and wake interaction : Optimization and control

   Författare :Karl Nilsson; Dan Henningson; Stefan Ivanell; Martin O. L. Hansen; KTH; []
   Nyckelord :Actuator disc method; Actuator line method; Blade element momentum method; Wind turbine wake; Wake interaction; CFD; LES; EllipSys3D;

   Sammanfattning : In the present thesis the wake flow behind wind turbines is analyzed numerically using large-eddy simulations. The wind turbine rotors are modeled by using either the actuator disc method or the actuator line method in which the blades are represented by body forces computed with airfoil data. LÄS MER

3. 2. Wind power wake modelling : Development and application of an actuator disc method for industrial utilization

   Författare :Nikolaos Simisiroglou; Stefan Ivanell; Thorsten Lutz; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Wind power; Offshore wind farm; Wakes; Actuator Disc Method ACD ; Computational Fluid Dynamics CFD ; Reynolds Average Navier–Stokes RANS ; WindSim; PHOENICS;

   Sammanfattning : As a wind turbine extracts energy from the wind it creates a region downstream where the wind velocity is decreased and the urbulence intensity is increased, this region is commonly called the wake region. Today’s wind farms include a large number of wind turbines position in tight layouts. LÄS MER

4. 3. Potential Flow Panel Methods for the Calculation of Free-surface Flows with Lift

   Författare :Carl-Erik Janson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; desingularized; shape optimization; Rankine source; waves; OCTOPUS; dipole; MMA; Dawson operator; boundary layer; vortex; Method of Moving Asymptotes; nonlinear; sailing yacht; four point operator; surface piercing wing; Navier-Stokes; numerical method; lift force; raised panel method; discrete Fourier transform; collocation point shift; potential flow; CFD; free surface; induced drag; SHIPFLOW; dispersion; damping; analytical method; hydrofoil;

   Sammanfattning : Two non-linear Rankine-source panel methods are developed and implemented in the same computer code. The first method uses a four-point upwind operator on the free-surface to compute the velocity derivatives and to enforce the radiation condition while the second method uses an analytical expression for the velocity derivatives and a collocation point shift one panel upstream to prevent upstream waves. LÄS MER

5. 4. Birds in the Flow: Flight Mechanics, Wake Dynamics and Flight Performance

   Författare :Mikael Rosén; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Djurekologi; Animal ecology; Eleonora s falcon.; hunting; optimum wingspan; tail posture; wingbeat kinematics; wake topology; DPIV; flight performance; wake dynamics; flight mechanics; wind tunnel; Flight; bird;

   Sammanfattning : I share my fascination of bird flight with many others, and here I summarise my thesis on the subject. This thesis emphasises the mechanics of bird flight by focusing on flight mechanics, wake dynamics and flight performance. LÄS MER

7. 5. Simulation and Analysis of a Novel Open Rotor Propeller - the Boxprop

   Författare :Alexandre Capitao Patrao; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wake Analysis Method; CFD; Open Rotors; Propfans; Tip vortex; CROR; Propellers;

   Sammanfattning : Economic factors and environmental awareness is driving the evolution of aircraft engines towards increasingly higher efficiencies, reaching for lower fuel consumption and lower emissions. The Counter-Rotating Open Rotor (CROR) is actively being researched around the world, promising a significantly increased propulsion efficiency relative to existing turbofans by employing two, counter-rotating propeller blade rows, thereby increasing the bypass ratio of the engine. LÄS MER