Vortilon Wingtip Flow Control for Stall Drag

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Solution Overview

Problem

Existing wing-tip designs for aircraft experience partial airflow separation at low speeds and high angles of incidence, leading to reduced lift and increased drag, which are not effectively addressed by current passive flow control devices.

Innovation Solution

A wing-tip arrangement featuring a vortilon attached to the lower surface of the winglet, which generates vortices to interfere with the boundary layer, delaying flow separation and maintaining lift while minimizing drag, with the vortilon's design and position tailored to specific flight conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a wing-tip arrangement with conventional passive flow control devices is used, then cruise drag is minimized, but low-speed airflow characteristics and lift at high angles of incidence deteriorate due to partial flow separation

Engineering Contradiction:

Improvecruise dragVSAvoidlow-speed airflow characteristics

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The vortilon is attached specifically to the lower surface of the wing-tip arrangement, creating a localized flow control feature that generates vortices only where needed. This local intervention delays flow separation at the wingtip during low-speed, high-angle-of-incidence conditions without adversely affecting cruise performance, as the vortex generation is confined to specific regions rather than affecting the entire wing structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of placing the flow control device on the upper surface of the winglet (conventional approach), the vortilon is inverted and attached to the lower surface. This unconventional positioning allows the vortex to interact with the boundary layer in a way that delays separation on the upper surface, effectively using the lower surface as the control point to influence upper surface flow behavior.

Inventive Principle:

Principle #13The other way round (Inversion)

2Use of energy by moving object

If wing-tip devices are used to reduce lift-induced drag, then fuel efficiency improves, but low-speed stall characteristics remain insufficient due to flow separation

Engineering Contradiction:

Improvefuel efficiencyVSAvoidflow separation at low speed

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The vortilon is positioned to generate vortices that act preliminarily on the boundary layer before flow separation can occur. By creating controlled vortices that energize the boundary layer in advance, the device prevents separation from developing during low-speed, high-angle-of-incidence conditions, thereby improving stall characteristics without compromising the drag-reducing benefits of the wingtip device during cruise.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If vortilons are attached to enhance low-speed characteristics, then lift at high angles of incidence is maintained, but device complexity increases

Engineering Contradiction:

Improvelow-speed stall characteristicsVSAvoidwing-tip arrangement complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The vortilon employs a simple, geometrically straightforward shape with a flat plate configuration that is easy to manufacture and install. This simplified geometry reduces manufacturing costs and installation complexity compared to more complex vortex generators or active flow control systems, making the solution economically viable despite the added component.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 wing-tip arrangement enhances low-speed airflow characteristics by generating vortices that improve boundary layer resistance to adverse pressure gradients, delaying flow separation and maintaining lift while minimizing drag penalties.

Implementation Method 1

at least one vortilon comprises a vortilon base and a vortilon tip, wherein the vortilon base is attached to at least one of the at least one lower surface of the wing-tip arrangement. The vortilon tip faces in a generally upstream direction.

Methodology Applied

Scientific EffectVortex generation: Vortex Ring

Implementation Method 2

Methodology Applied

Scientific EffectBoundary layer control: Boundary Layer

Data Source

PatentUS10773796B2Wing-tip arrangement having vortilons attached to a lower surface, and aircraft having such a wing-tip arrangement and the use of vortilons on a wing-tip arrangement

Publication Date: 2020.09.15 AIRBUS OPERATIONS GMBH

AI summary

A wing-lip arrangement couplable with a wing of an aircraft includes a connection region for coupling or integration with the wing end region, at least one tip, at least one upper surface and at least one lower surface, which extend between a leading edge and a trailing edge of the wing-tip arrangement from the connection region to the at least one tip, and at least one vortilon. The local dihedral of the wing-tip arrangement changes between the at least one tip and the connection region, such that at least a part of the wing-tip arrangement projects at an angle relative to the wing. The at least one vortilon includes a vortilon base and a vortilon tip. The vortilon base is attached to at least one of the at least one lower surface of the wing-tip arrangement. The vortilon tip faces in an upstream direction.