Underwater Appendage Assembly Flapping Propulsion
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Solution Overview
Problem
Existing wave-harnessing technologies for marine vessels, such as Waveglider and Autonaut, rely on flat solid foils that do not fully utilize the pitching motion of the vessel to maximize propulsion efficiency.
Innovation Solution
An underwater appendage assembly featuring a rudder foil with a flapper member, constructed from resiliently flexible materials, that induces a flapping action when the vessel pitches, enhancing propulsion through a pair of wing-shaped fins or flapper blades connected to the rudder foil, which are tapered to maximize deflection and promote forward motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flat solid foils are used for wave-harnessing propulsion, then the structure is simple and robust, but the propulsion efficiency is limited and pitching motion is not fully utilized
Solution Approach 1:
The patent applies the dynamics principle by transforming the static flat solid foil into a dynamic structure with a flapper member that can deflect and flap during vessel pitching. The flapper member is connected to the rudder foil and moves relative to it, converting the vessel's pitching motion into useful flapping action that generates additional propulsion thrust, thereby fully utilizing the pitching motion to improve propulsion efficiency.
Solution Approach 2:
The patent applies segmentation by dividing the appendage into distinct functional components: the rudder foil and the flapper member. The flapper member is further segmented into a resiliently flexible portion and a rigid or semi-rigid flapper blade. This segmentation allows each component to perform its specific function - the rudder foil provides structural support and steering, while the flapper member generates propulsion through flapping motion.
2Productivity
If resiliently flexible materials are used for the flapper member, then pitching motion is effectively utilized for propulsion, but the material selection and manufacturing become more complex
Solution Approach 1:
The patent applies parameter changes by specifying that the flapper member be constructed from resiliently flexible materials with specific mechanical properties that allow it to deflect during pitching motion. The material parameters (flexibility, resilience) are optimized to enable effective energy absorption and release during the flapping cycle, maximizing propulsion effectiveness while accommodating the dynamic loading conditions.
3Productivity
If wing-shaped fins are used instead of flat plates, then propulsion is enhanced through tapered design, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by implementing tapered thickness in the wing-shaped fins, where the cross-section varies along the span to optimize hydrodynamic performance. The fins are thickest at the root for structural strength and gradually taper toward the tips to reduce drag and improve flow attachment. This local variation in geometry allows the structure to achieve both strength and propulsion efficiency.
4Productivity
If multiple flapper members are spaced vertically, then endplate effect and propulsion are improved, but the device complexity and number of parts increase
Solution Approach 1:
The patent applies merging by combining multiple flapper members into a single integrated assembly that is vertically spaced along the appendage. The lowermost flapper member is integrated with the endplate function, merging the propulsion-generating flapper members with the structural endplate into a unified component that serves both hydrodynamic and structural purposes.
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 flapper member's deflection enhances propulsion by synchronizing with the vessel's pitching motion, providing effective forward thrust with reduced mechanical noise and likelihood of breakage, while allowing independent action in rolling seas and improving steerage and station-holding capabilities.
Implementation Method 1
the flapper member is at least in part constructed of a resiliently flexible material whereby pitching of the vessel effects the deflection of the resiliently flexible part of the flapper member
Data Source
AI summary
The present invention is directed broadly to an underwater appendage assembly (10) of a marine vessel (12). The underwater appendage assembly (10) is in the form of a rudder assembly fitted to a bow section (14) of the vessel (12). The rudder assembly comprises an appendage in the form of a rudder foil (18) connected to a flapper member (20). The flapper member (20) is arranged whereby movement and more particularly pitching, of the vessel (12) induces deflection of the flapper member (20) relative to the rudder foil (18). This deflection in the flapper member (20) provides an oscillating movement of the flapper member (20) in a flapping action which is substantially synchronised with movement of the vessel (12) upward and downward. The flapping action of the flapper member (20) is effective in promoting forward propulsion of the vessel (12).