Trailing-Edge Lift Control Using a Controllable Protuberance
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Solution Overview
Problem
Existing methods for actively controlling lift forces on lifting surfaces, such as wings and wind turbine blades, are complex and lead to reliability issues, high costs, and safety concerns due to unsteady forces caused by turbulence and wind gusts.
Innovation Solution
A controllable lift device featuring a protuberance with a rotatable or translatable member that can adjust the lift by modifying the separated flow region, using a motor and controller to change the orientation or position of the member, potentially combined with plasma actuators, to manage lift forces in response to changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex active control techniques (movable flaps, boundary layer blowing/suction, synthetic jets, microtabs) are used to control lift forces, then lift control capability is improved, but device complexity increases leading to reliability problems, high capital cost, high energy cost, and safety issues
Solution Approach 1:
The lifting surface is divided into multiple segments along the span, with each segment equipped with independent plasma actuators that can be controlled separately. This segmentation allows localized lift control without requiring complex mechanical flap systems, thereby improving adaptability while reducing overall system complexity
Solution Approach 2:
The patent replaces traditional mechanical active control systems (movable flaps, synthetic jets, microtabs) with plasma actuators that use electrical discharges to directly manipulate the boundary layer and control lift forces. This substitution eliminates complex mechanical linkages, moving parts, and high-energy consumption systems while maintaining effective lift control capability
2Strength
If lifting surfaces are built strong and heavy to counter anticipated unsteady forces, then structural strength is improved, but weight and cost increase
Solution Approach 1:
The plasma actuators are positioned to preemptively counteract unsteady forces before they cause significant structural loading. By detecting and responding to turbulence and wind gusts in real-time, the system prevents extreme loads from developing, allowing for lighter structural design while maintaining safety margins
Solution Approach 2:
The system dynamically changes aerodynamic parameters (lift force distribution) in response to varying flight conditions and unsteady forces. This active parameter adjustment allows the structure to experience reduced peak loads compared to passive designs, enabling weight reduction while maintaining strength where needed
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 device allows for precise control of lift forces, reducing structural fatigue and costs by actively managing lift in response to turbulence and wind shear, enhancing the reliability and safety of lifting surfaces.
Implementation Method 1
the protuberance creating a region of separated flow downstream of the protuberance
Implementation Method 2
a motor and controller to change the orientation or position of the member
Data Source
AI summary
A lift control device actively controls the lift force on a lifting surface. The device has a protuberance near a trailing edge of its lifting surface, which causes flow to separate from the lifting surface, generating regions of low pressure and high pressure which combine to increase the lift force on the lifting surface. The device further includes a means to keep the flow attached around the protuberance or to modify the position of the protuberance in response to a command from a central controller, so as to provide an active control of the lift between a maximum value and a minimum value.