Variable Foil Machine Oscillation Amplitude
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Solution Overview
Problem
Current oscillating foil machines are limited by small scale systems with limited oscillation amplitude and power output, requiring additional tensioning, trimming, and actuating devices or articulated foil combinations to initiate and sustain oscillations, which restricts their energy harvesting and propulsion capabilities.
Innovation Solution
The Variable Foil Machine employs a flexible, dynamically profiled foil with a trailing and leading draft member system, secured to a pivoting carrier, which oscillates to convert fluid flow energy into mechanical movement, driving an energy converter for power generation and fluid propulsion, utilizing materials like fabrics, composites, and polymers for optimal fluid-dynamic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If additional tensioning, trimming, and actuating devices are used to initiate and sustain oscillations, then oscillation stability is improved, but device complexity increases
Solution Approach 1:
The foil is designed to automatically initiate and sustain oscillations through its own aerodynamic properties without requiring external actuating devices. The flexible foil self-adjusts its angle of attack and camber during oscillation, creating aerodynamic forces that naturally sustain the motion cycle.
Solution Approach 2:
The foil transitions from a static structure to a dynamically flexible structure that can change its shape and orientation during operation. This dynamic flexibility allows the foil to adapt its aerodynamic characteristics during oscillation, enabling self-sustained motion without additional control mechanisms.
2Reliability
If articulated foil combinations are used to initiate and sustain oscillations, then oscillation reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The foil is divided into multiple flexible segments or zones that can independently deform during oscillation. This segmentation allows each portion to contribute to the overall oscillation mechanism, improving reliability while maintaining a relatively simple single-piece or easily assembled structure.
Solution Approach 2:
The foil's aerodynamic parameters such as camber, twist, and angle of attack are allowed to change dynamically during oscillation rather than being fixed. This parameter variability enables the foil to maintain reliable oscillation across different operating conditions without requiring complex articulated mechanisms.
3Stability of the object's composition
If tensioned sheet between aligned support members is used, then structural stability is improved, but oscillation amplitude is reduced
Solution Approach 1:
The support structure transitions from rigid aligned members to a dynamic system that allows controlled movement and deformation. The foil and its supports can flex and move together, maintaining structural integrity while enabling larger oscillation amplitudes through coordinated motion.
Solution Approach 2:
The tensioned sheet evolves into a flexible foil structure that can undergo large deformations during oscillation. This flexible structure maintains aerodynamic stability through its controlled flexibility rather than rigid constraint, allowing both structural stability and large oscillation amplitudes.
4Stability of the object's composition
If fixed position support members are used, then structural stability is improved, but energy capture cross section area is reduced
Solution Approach 1:
The support members transition from fixed positions to dynamically adjustable positions that can move with the oscillating foil. This dynamic support system maintains structural stability through controlled motion while allowing the foil to achieve larger amplitudes and present a larger effective area to the fluid flow for energy capture.
Solution Approach 2:
The support structure adds a temporal dimension to what was previously a static spatial arrangement. By allowing supports to move in time with the oscillation cycle, the system maintains stability while expanding the effective energy capture area through increased foil excursion and dynamic positioning.
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
This design enhances energy capture and propulsion efficiency by allowing larger oscillation amplitudes and power output, simplifying construction, and reducing component count, while being adaptable for various fluid flow conditions and applications.
Implementation Method 1
A foil, sail, wing, airfoil or hydrofoil has a leading edge, leading into the flow of a fluid, and a trailing edge, downstream of the leading edge
Implementation Method 2
This design relies on the natural tendency for thin sheets of materials to flutter in the wind or aeroelastic flutter
Data Source
AI summary
The Variable Foil Machine harnesses fluid flow energy and propels fluids. A flexible foil (120) with reversible camber is secured to leading draft member (150) on leading support (122) and to trailing draft member (130). The trailing draft member (130) is secured to trailing guide (132), movable on trailing support (136). Apparatus can be installed on the ground or a craft via pivoting carrier (138), for alignment with fluid flow. In one embodiment, trailing draft member (130) reciprocates between support members 136l and 136r, upon oscillation of the foil (120). In other embodiments, a reciprocation amplitude offset between leading draft member (150) and trailing draft member (130) promotes cyclic translation of the foil (120) and linkage thereto. An energy converter (142) may be cooperatively coupled to produce energy or perform work. Integration of foil oscillations into rotary movement via a crank arm (48) is also embodied.