Cooperating Fin Vortex Generator for Lower Drag Lift Control
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Solution Overview
Problem
Existing vortex generators increase maximum lift but also increase parasitic drag, which is undesirable for lifting bodies.
Innovation Solution
A vortex generator design with fins arranged to form a cooperating system, where the airflow from one fin is directed towards another, forming a single vortex, and featuring aerofoil-shaped sections with concave portions to reduce drag while maintaining or enhancing lift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional vortex generators are used to increase maximum lift, then the stall margin is improved, but parasitic drag increases at all pre-stall angles of attack
Solution Approach 1:
The vortex generator is divided into multiple fins (first fin, second fin, and optionally third fin) arranged in sequence along the airflow direction. Each fin has specific dimensions and spacing that segment the vortex generation process, allowing control over vortex strength and distribution to reduce parasitic drag while maintaining lift enhancement
Solution Approach 2:
Different fins have different characteristics (length, height, spacing) optimized for their specific positions in the airflow. The first fin has length L1 and height H1, the second fin has length L2 and height H2, with specific spacing S between them. This local optimization allows each fin to perform its specific function efficiently, reducing overall drag while maintaining effective boundary layer control
2Reliability
If multiple fins are arranged adjacently to increase lift effectiveness, then the maximum lift coefficient is improved, but device complexity increases
Solution Approach 1:
The invention specifies optimal parameter ranges for fin dimensions and spacing: the spacing S between fins is 0.05c to 0.15c (where c is chord length), the ratio L2/L1 is 0.5 to 0.8, and the ratio H2/H1 is 0.8 to 1.2. These parameter relationships provide a systematic design approach that achieves effective vortex generation without requiring excessive complexity or trial-and-error design
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 new design reduces parasitic drag while maintaining or improving lift, offering a more effective and cost-efficient solution compared to prior art vortex generators.
Implementation Method 1
Since the small fin is arranged at an angle to the flow over the wing, the fin thereby generates a vortex over the surface of a wing. This delays flow separation of the boundary layer as the vortex entrains higher energy fluid away from the surface and draws it down to energise the boundary layer.
Implementation Method 2
This delays flow separation of the boundary layer as the vortex entrains higher energy fluid away from the surface and draws it down to energise the boundary layer.
Implementation Method 3
said concave portion is arranged such that the airflow passing over the first fin is directed towards the suction surface of the second fin
Data Source
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AI summary
Vortex generator comprising a first fin and a second fin, said first fin being arranged upstream of said second fin. The first fin and the second fin are arranged such that the shortest distance between the trailing edge of the first fin and the leading edge of the second fin is less than 50% of the length of the first fin and such that the first fin and the second fin are arranged such that the first fin affects the flow of air passing the first fin such that it is directed towards the second fin. In this way a vortex generator is provided which shows lower drag while maintaining the same lift improvement as prior art type vortex generators.