Wind Turbine Tower Ring Elements Suppress Vortex Vibrations
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Solution Overview
Problem
Wind turbine towers experience significant transverse vibrations due to eddy-excited oscillations, particularly when not in operation or during construction, which existing solutions fail to adequately address.
Innovation Solution
A tubular or conical tower design featuring aerodynamically effective cylindrical or conical ring elements with a diameter at least 1.05 times the tower's outer diameter and length at least half the diameter, attached at specified intervals to reduce vortex-induced vibrations, using materials like fiber composites, wood, or plastics, and optionally magnetically secured.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the tower is made very high to increase energy generation capacity, then the power output is improved, but the tower becomes more susceptible to eddy-excited transverse vibrations
Solution Approach 1:
The tower surface is segmented by attaching discrete ring elements at specific intervals along the tower height. These rings divide the continuous tower surface into segments, disrupting the coherent vortex formation that causes strong transverse vibrations, while allowing the tower to maintain its full height for power generation.
Solution Approach 2:
Ring elements are introduced as intermediary structures between the wind flow and the tower. These rings modify the flow dynamics by generating three-dimensional vortices that interfere with the two-dimensional Karman vortex street, thereby reducing the harmful transverse vibrations on the tower.
2Object-affected harmful factors
If conventional vibration reduction measures like Scruton spirals are used, then some vortex effects are reduced, but they do not adequately prevent eddy-excited transverse vibrations on tall towers
Solution Approach 1:
The invention transitions from two-dimensional vortex control (Scruton spirals wrapping around the tower) to three-dimensional vortex control using ring elements that extend radially outward. This dimensional change creates more effective flow disruption, generating complex three-dimensional vortex patterns that superiorly suppress eddy-excited transverse vibrations compared to conventional two-dimensional measures.
3Object-affected harmful factors
If ring elements with diameter at least 1.05 times the tower diameter are attached, then Karman vortex street formation is suppressed, but the device complexity increases
Solution Approach 1:
The invention specifies precise geometric parameters for the ring elements (diameter at least 1.05 times the tower diameter, length at least half the diameter) to optimize vortex suppression. By carefully controlling these parameters, the rings achieve effective Karman vortex street suppression while maintaining relatively simple structures that can be manufactured and installed with standard procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The ring elements effectively suppress Karman vortex street formation, reducing transverse vibrations and turbulence, enhancing the structural stability and operational efficiency of wind turbines by modifying the flow dynamics around the tower.
Implementation Method 1
A well-known phenomenon is the Kärmän vortex street, in which counter-rotating vortices form behind a body in a flow. Such vortices can excite the tower of a wind turbine to oscillate.
Implementation Method 2
Surrounding the tower at least at a predetermined height is an aerodynamically effective ring member concentric with the longitudinal axis of the tower. The ring element has an outer surface with a diameter and a length, the diameter being at least 1.05 times the outer diameter of the tower at the predetermined height and the length of the outer surface being at least half this outer diameter.
Data Source
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Figure 2
AI summary
The invention relates to a tower for a wind turbine, to which at least one aerodynamically effective ring element is attached to prevent vortex-induced vibrations. This ring element concentrically surrounds the tower at a predetermined height and has a lateral surface with a diameter and length, wherein the diameter of the lateral surface is at least 105% of the outer diameter of the tower at the predetermined height and the length of the lateral surface is at least 50% of this outer diameter. The invention further relates to a method for erecting a wind turbine.