Vortex Generating Apparatus for Dynamic Stall Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing technologies face challenges in controlling and utilizing the dynamic stall vortex, which generates high non-steady negative pressure and dynamic lift, leading to instability in fluid dynamics applications such as aircraft and windmills, as they typically aim to prevent its occurrence by keeping the angle of attack below the stall angle.
Innovation Solution
A vortex generating apparatus that includes a wing member with a stagnation point and separation points, a disturbance applying unit to alter the boundary layer adhesion distance, and a controller to temporally control disturbances, allowing for the generation of a dynamic stall vortex without changing the wing's angle of attack, by applying disturbances through methods like discharge, vibration, or acoustic waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the angle of attack is increased to generate dynamic stall vortex for high dynamic lift, then the dynamic lift increases, but the dynamic lift becomes unstable and rapidly decreases causing complete stall
Solution Approach 1:
The invention applies dynamic control to the boundary layer adhesion distance through time-varying disturbances, transforming the static flow separation problem into a dynamically controllable process. By periodically adjusting the adhesion distance, the system generates dynamic stall vortices on demand while maintaining overall stability, resolving the contradiction between achieving high dynamic lift and maintaining stability.
Solution Approach 2:
The invention employs periodic disturbance application to the boundary layer, creating cyclic variations in adhesion distance that generate dynamic stall vortices at controlled intervals. This periodic action allows the system to achieve high dynamic lift through vortex generation while preventing complete stall by resetting the boundary layer state between cycles, thus maintaining stability.
2Stability of the object's composition
If the angle of attack is kept below the stall angle to prevent dynamic stall vortex generation, then the dynamic lift remains stable, but the opportunity to utilize high dynamic lift and negative pressure effects is lost
Solution Approach 1:
The invention applies preliminary disturbance to the boundary layer before natural separation occurs, controlling the adhesion distance proactively rather than reactively. This preliminary action enables the system to generate dynamic stall vortices at optimal moments without exceeding the static stall angle, thereby maintaining stability while enabling versatile utilization of vortex characteristics for various applications.
Solution Approach 2:
The invention changes the boundary layer parameters (adhesion distance, disturbance intensity, frequency) independently of the angle of attack. By controlling these parameters through disturbance application, the system can generate dynamic stall vortices and utilize their high negative pressure characteristics while keeping the angle of attack below the stall angle, thus achieving both stability and adaptability.
3Adaptability or versatility
If disturbance is applied to change boundary layer adhesion distance to generate dynamic stall vortex, then controlled vortex generation is achieved, but the device complexity increases
Solution Approach 1:
The invention replaces complex mechanical systems for vortex generation with non-contact disturbance methods such as acoustic waves, electromagnetic fields, or thermal effects. These substitution methods can alter boundary layer adhesion distance without moving parts or complex mechanical structures, achieving controlled vortex generation while minimizing device complexity.
Solution Approach 2:
The invention introduces an intermediary disturbance mechanism that couples the control system to the boundary layer without direct mechanical contact. This intermediary (such as acoustic waves or electromagnetic fields) transfers energy to the boundary layer to control adhesion distance, simplifying the overall system architecture while enabling versatile vortex generation control.
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
Enables the controlled generation of dynamic stall vortices, allowing for enhanced lift, improved fluid mixing, and reduced noise or vibration, while maintaining stability in fluid dynamics applications.
Implementation Method 1
a disturbance applying unit configured to apply a disturbance to an upstream side of the first separation point to cause part of a boundary layer of the flow to adhere
Implementation Method 2
the first and the second separation points being followed by a first and a second separation region respectively
Implementation Method 3
swing the boundary layer so as to generate a dynamic stall vortex in the separation region, the dynamic stall vortex having an axis in a wing span direction of the member
Data Source
AI summary
A vortex generating apparatus includes: a member to contact with a flow of a fluid to form a stagnation point and a first and a second separation points on a periphery of a cross section of the member parallel to the flow; a disturbance applying unit to apply a disturbance to an upstream side of the first separation point to cause part of a boundary layer of the flow to adhere; and a controller to temporally control the application of the disturbance to change an adhesion distance from the stagnation point to the first separation point so as to generate a dynamic stall vortex.