Aerodynamic tower shake force analysis for VAWT

Journal Article · Fri Feb 01 04:00:00 EST 1985 · J. Sol. Energy Eng.; (United States)

DOI:https://doi.org/10.1115/1.3267652· OSTI ID:5635640

Loth, J L

Vertical axis wind turbines (VAWT) are subjected to blade lift forces which vary continuously in both magnitude and direction. These blade lift forces are transmitted via the blade support arms to the tower. The resulting tower force vector is a composite of: a downwind and a crosswind average force component, rotating force vectors, and force vectors oscillating in the crosswind direction. The frequency of the rotating and oscillating forces are multiples of the product of Bw, where B is the number of blades used and ..omega.. is the rotor angular velocity. The magnitude of the largest tower shake force vector is of the same order as the average downwind force component, and may represent a serious design constraint in the calculation of the required tower stiffness. A closed-form solution for the tower force vectors has been derived, by introducing a suitable wind interference model. It shows that the magnitude of the largest tower shake force vector, using a threebladed rotor, is four times smaller than a two-bladed rotor. The Betz limit and the optimum tip speed ratio as a function of solidity has been derived by comparison with two semicylindrical actuators in series.

• Research Organization: Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, W.Va.
• OSTI ID: 5635640
• Journal Information: J. Sol. Energy Eng.; (United States), Journal Name: J. Sol. Energy Eng.; (United States) Vol. 107:1; ISSN JSEED
• Country of Publication: United States
• Language: English

Related Subjects

17 WIND ENERGY
170602* -- Wind Energy Engineering-- Turbine Design & Operation
AERODYNAMICS
ANGULAR VELOCITY
DYNAMIC LOADS
FLOW STRESS
FLUID MECHANICS
MACHINERY
MECHANICAL STRUCTURES
MECHANICS
ROTORS
STRESSES
SUPPORTS
TURBINE BLADES
TURBINES
TURBOMACHINERY
VELOCITY
VERTICAL AXIS TURBINES
WIND LOADS
WIND TURBINES