Annular Tower Surface Structure for Vortex-Induced Vibration Suppression
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Solution Overview
Problem
The installation of wind turbines is restricted by regional wind conditions, leading to instability and safety issues during hoisting and installation, due to vortex-induced vibrations, which existing solutions like spiral wires do not adequately address, especially concerning noise and long-term operation.
Innovation Solution
An enclosure with a convex-concave outer surface and air guiding grooves is designed to disrupt the boundary layer, preventing vortex-induced vibrations by altering the airflow and reducing the correlation of fluctuating pressures, thus suppressing the formation of Karman vortex streets and resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spiral wires or plates are wound around the tower outer wall to suppress vortex-induced vibrations, then the vibration suppression effect is improved, but the noise increases and the solution is not suitable for long-term operation
Solution Approach 1:
The invention changes the surface geometry parameters of the tower by introducing annular recesses and bosses with specific dimensional relationships (depth-to-diameter ratios, spacing distances). This geometric parameter modification disrupts the boundary layer flow without generating excessive noise, unlike spiral wires. The air guiding grooves on the bosses further optimize flow control by directing air into the recesses, achieving vibration suppression through controlled flow disturbance rather than continuous spiral structures.
Solution Approach 2:
The tower surface is segmented into alternating annular recesses and bosses, creating a discrete pattern rather than a continuous spiral structure. This segmentation allows the flow to be disturbed at specific locations and intervals, reducing the cumulative noise generation while maintaining the vortex suppression effect. The segmented approach also eliminates the need for continuous spiral wires that generate constant noise.
2Adaptability or versatility
If the tower is hoisted and installed in segments under regional wind conditions, then the installation flexibility is improved, but vortex-induced vibrations cause instability and safety issues
Solution Approach 1:
The vibration suppression structure (annular recesses and bosses) is pre-installed as an integral part of the tower segments before hoisting and assembly. This preliminary integration ensures that the flow disruption mechanism is already in place during the installation process, providing stability from the outset rather than attempting to control vibrations during the hoisting operation itself. The structure is prepared in advance to handle the wind conditions encountered during segmented installation.
3Reliability
If the outer surface of the enclosure is provided with a convex-concave structure with air guiding grooves, then the vortex-induced vibration suppression is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention defines specific parameter ranges for the annular recesses and bosses (depth between 0.01-0.05 times the tower diameter, spacing distances, groove dimensions) to optimize the balance between vibration suppression effectiveness and manufacturing feasibility. These parameter specifications allow the complex geometry to be produced using standard manufacturing tolerances and processes, reducing the actual manufacturing complexity despite the increased structural detail.
Solution Approach 2:
The complex convex-concave structure with air guiding grooves is applied locally at specific locations and intervals along the tower, rather than requiring continuous complex features throughout. The annular recesses and bosses are distributed at optimized spacing, providing vibration suppression where needed while leaving large portions of the tower surface simple and easy to manufacture. This localized application of complexity reduces overall manufacturing difficulty.
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 solution effectively reduces vortex-induced vibrations, allowing for safer and more efficient installation and long-term operation by disrupting the boundary layer and reducing noise, while maintaining structural integrity and adhering to environmental standards.
Implementation Method 1
disrupt the boundary layer formed by the upwind incoming flow around the enclosure
Implementation Method 2
preventing the formation of Karman vortex streets and resonance
Data Source
Figure 1-1
Figure 1-2
Figure 2
AI summary
An enclosure having an outer surface with a vortex-induced vibration suppression function is provided. The outer surface of the enclosure is provided with a plurality of annular recesses surrounding the enclosure, such that alternately concave and convex annular recesses and annular bosses configured for disrupting a boundary layer of a laminar flow are formed on the outer surface of the enclosure. An outer surface of the annular boss is provided with a plurality of air guiding grooves, and the plurality of air guiding grooves are distributed in a circumferential direction of the annular boss. The air guiding grooves are inclined upward or downward, such that part of an upwind incoming flow flowing to the annular boss can be guided into the annular recesses adjacent to the annular boss via the air guiding grooves. With the convex-concave outer surface, the correlation of the flowing and flowing states of the boundary layers can be disrupted, and the consistency of fluctuating pressures can be avoided, thus preventing the cause of formation of the vortex-induced vibration fundamentally. The air guiding grooves cause deviation of the upwind incoming flow, and then further disrupts the correlation of flowing and flowing states of the boundary layers between the annular bosses and the annular recesses, and the noise generated is also small.