Control Surface Arrangement With Vortex-Induced Flow Attachment
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Solution Overview
Problem
Conventional flapped rudders experience early and severe flow separation, leading to increased drag and reduced lift-to-drag ratio, and existing active flow control devices are complex.
Innovation Solution
A control surface arrangement with a vortex generator surface that induces vortices in the fluid flow, comprising projections on the leading edge, side, and between control surface portions to maintain flow attachment and reduce separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional flapped rudder is used to control fluid flow, then the control surface can be moved to generate lift, but flow separation occurs early and severely, increasing drag and reducing lift-to-drag ratio
Solution Approach 1:
The vortex generator surface is positioned upstream of the control surface to pre-condition the flow by generating beneficial vortices before the flow encounters the control surface. This preliminary action modifies the boundary layer characteristics in advance, preventing flow separation when the control surface is deflected at high angles, thereby maintaining lift-to-drag ratio while preserving control effectiveness
2Reliability
If active flow control devices are proposed to address flow separation, then flow attachment can be improved, but the devices are complex
Solution Approach 1:
The vortex generator surface is segmented into multiple discrete vortex generating elements distributed along the upstream portion of the control surface. Each element independently generates vortices that contribute to flow attachment. This segmentation allows the complex flow control function to be achieved through multiple simple, identical components rather than a single complex device, reducing manufacturing difficulty and maintenance requirements
Solution Approach 2:
The vortex generator surface is merged with the control surface structure, forming an integrated assembly where the vortex generating elements are part of the control surface itself. This merging eliminates the need for separate, standalone active flow control devices, reducing overall system complexity while maintaining the ability to prevent flow separation through vortex generation
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 vortex generator surface arrangement enhances flow attachment, improving lift performance, reducing drag, and maintaining efficiency even at high angles of attack, while simplifying construction and operation.
Implementation Method 1
a vortex generator surface arrangement arranged to induce vortices in a fluid flow passing over the first control surface portion and/or the second control surface portion
Data Source
AI summary
There is provided a control surface arrangement for influencing fluid flow about a vehicle, the control surface arrangement comprising: a first control surface portion; a second control surface portion, the second control surface provided downstream of the first control surface portion relative to a fluid flow direction, the second control surface portion configured to be moveable relative to the first control surface portion; and a vortex generator surface arrangement arranged to induce vortices in a fluid flow passing over the first control surface portion and/or the second control surface portion.