Author: Erik Mollerstrom, Fredric Ottermo, Anders Goude, Sandra Eriksson, Jonny Hylander, Hans BernhoffPublication: Wind EnergyYear Published: 2016 The relation between power performance and turbulence intensity for a VAWT H-rotor is studied using logged data from a 14 month (discontinuous) period with the H-rotor operating in wind speeds up to 9 m/s. The turbine, designed originally…
Author: Erik Mollerstrom, Fredric Ottermo, Anders Goude, Sandra Eriksson, Jonny HylanderPublication: J. Physics: Conference SeriesYear Published: 2019 The influence of turbulence intensity (TI) on the tip speed ratio for maximum power coefficient, here called λCp_max, is studied for a 200 kW VAWT H-rotor using logged data from a 14 month period with the H-rotor operating…
Author: Robert Reuter, Mark WorstellPublication: Sandia National LaboratoriesYear Published: 1978 Torque ripple is a name given to time variations in torque which are propagated through the drive train of wind energy conversion systems.This paper covers an analytical and experimental investigation of torque ripple in a Darrieus vertical axis wind turbine. An analytical model of the…
Author: Curtis DoddPublication: Sandia National LaboratoriesYear Published: 1977 This report contains the results of lightning protection studies for Vertical Axis Wind Turbines. The methodology is established for determining the chances for a lightning strike at a VAWT site. Proposed designs include an insulator design, a brush by-pass design, a cone of protection, lightning elimination device,…
Author: Thomas Carne, Arlo NordPublication: Sandia National LaboratoriesYear Published: 1982 A testing technique has been developed to measure the modes of vibration of a rotating vertical axis wind turbine. This technique has been applied to the Sandia 2-m turbine, where the changes in individual modal frequencies as a function of the rotational speed have been…
Author: James Lauffer, Thomas Carne, Thomas AshwillPublication: Sandia National LaboratoriesYear Published: 1988 In the design of large, flexible wind turbines subjected to dynamic loads, knowledge of the modal frequencies and mode shapes is essential in predicting structural response and fatigue life. During design, analytical models must be depended upon for estimating modal parameters. When turbine…
Author: Thomas Carne, Donald Lobitz, Arlo Nord, Robert WatsonPublication: Sandia National LaboratoriesYear Published: 1982 A finite element procedure, which includes geometric stiffening, and centrifugal and Coriolis terms resulting from the use of a rotating coordinate system, has been developed to compute the mode shapes and frequencies of rotating structures. Special application of this capability has…
Author: Todd Griffith, Randy Mayes, Patrick HunterPublication: Sandia National LaboratoriesYear Published: 2010 A simple modal test to determine the first tower bending mode of a 60 kW (82 feet tall) vertical axis wind turbine was performed. The minimal response instrumentation included accelerometers mounted only at easily accessible locations part way up the tower and strain…