Underwater Turbine Array Stability via Tethered Buoyancy
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Solution Overview
Problem
Underwater turbine arrays face challenges in maintaining stability in stream flow while transitioning from an underwater generating condition to a surface maintenance condition, particularly when using a surface piercing element is not feasible, and relying on active ballast adjustment is undesirable due to reliability and power consumption concerns.
Innovation Solution
A mounting system with a tether connected to a primary underwater anchorage and a rigid fixed length stay to a secondary anchorage, allowing pivoting or rollover transitions without disconnection, and incorporating variable ballast for buoyancy control to move between operating and maintenance conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a surface piercing element is used to achieve pitch control, then pitch stability is improved, but obstruction to shipping occurs and countermeasures are required
Solution Approach 1:
The invention removes the surface-piercing element from the system entirely. Pitch control is achieved through the interaction between the turbine array and the water surface tension, allowing the array to self-align with the flow direction without any part protruding above water, thus eliminating shipping obstruction while maintaining pitch stability
Solution Approach 2:
The water surface acts as an intermediary medium that provides pitch stability. The turbine array utilizes surface tension and wave interaction as a natural mediator to achieve directional alignment, replacing the need for mechanical surface-piercing pitch control mechanisms
2Stability of the object's composition
If active adjustment of turbine ballast is used to maintain pitch stability, then pitch control is achieved, but reliability decreases and power consumption increases
Solution Approach 1:
The turbine array automatically achieves and maintains pitch stability through its interaction with water surface forces. The system self-regulates its orientation without requiring active ballast adjustment mechanisms, controllers, or power consumption, thereby improving reliability and reducing operational complexity
Solution Approach 2:
The invention replaces active mechanical ballast adjustment systems with passive hydrodynamic and surface tension-based pitch control. The natural forces of water interaction provide the stabilization mechanism, eliminating the need for motors, sensors, and control systems associated with active ballast adjustment
3Stability of the object's composition
If a secondary restraint is added to maintain turbine position, then position stability is improved, but device complexity increases and movement between conditions is obstructed
Solution Approach 1:
The tether system performs multiple functions simultaneously: it provides primary anchorage, enables pitch control through surface interaction, allows transition between operating and maintenance conditions, and maintains position stability. This multi-functionality eliminates the need for separate secondary restraints, reducing structural complexity while achieving position stability
4Stability of the object's composition
If the turbine array is designed for stable operation in stream flow, then operational stability is improved, but transition to surface maintenance condition becomes difficult
Solution Approach 1:
The tether length is made dynamically adjustable, allowing the system to adapt its configuration. During operation, the tether provides stable anchorage; during maintenance transition, the tether length can be increased to allow the array to roll onto its side and expose turbines to air, thus maintaining operational stability while enabling easy maintenance access
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
Enables stable operation in stream flow and easy transition to surface maintenance without obstructing shipping or requiring complex secondary restraints, maintaining turbine array heading and reducing complexity in underwater structures.
Implementation Method 1
by increasing buoyancy thereof can be brought to the surface whilst remaining tethered
Data Source
Figure 1~2
Figure 3~4
AI summary
An array of underwater turbines is mounted frame which is tethered to the underwater surface. A fixed length yaw restraint provides stability in a fully submerged condition. The array can be brought to the surface by change of buoyancy without disconnection or length adjustment of the yaw restraint. Several embodiments are disclosed.