Flow Past Airfoil
Flow past a stationary NACA 0012 airfoil at an angle of attack of 20°. Variations in Reynolds number influence flow separation and vortex dynamics. The objective is to improve aerodynamic efficiency by increasing the lift-to-drag ratio.
Task difficulty is set by the Reynolds number, with higher values producing sharper flow separation and stronger turbulence.
Environment List
2D Airfoil
Environment ID |
Re |
|---|---|
|
1×10³ |
|
3×10³ |
|
5×10³ |
3D Airfoil
Environment ID |
Re |
|---|---|
|
1×10³ |
|
3×10³ |
|
5×10³ |
Reward
The reward at step \(t\) maximizes aerodynamic efficiency:
where \(\langle \cdot \rangle_{T_{\mathrm{act}}}\) denotes the average over the actuation interval and the reference values correspond to the uncontrolled baseline.
Action Space
Actuation uses surface-mounted synthetic jet actuators placed on top of the airfoil. Zero net-mass-flux is enforced across actuators.
In 3D, the domain is extended spanwise (depth \(D = 1.4\)), yielding four spanwise jet segments and 12 individual actuators in total.
In MARL mode, each agent controls a group of three adjacent jets (one spanwise segment), enabling decentralized control over independent surface regions.
As in the cylinder environment, the raw control signal is temporally smoothed via exponential filtering with \(\alpha = 0.1\).
Observation Space
Observations consist of velocity components at sensor locations distributed around the airfoil surface (analogous to the cylinder setup). The 3D configuration follows the same layout as the 2D case but extends sensor placement spanwise.
Difficulty Levels
Difficulty is controlled by the Reynolds number:
Level |
Reynolds number |
|---|---|
Easy |
Re = 1×10³ |
Medium |
Re = 3×10³ |
Hard |
Re = 5×10³ |
Higher Reynolds numbers lead to more abrupt flow separation and stronger turbulence, which increases the challenge of effective flow control.
API Reference
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Environment for 2D airfoil aerodynamic efficiency improvement. |
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Environment for 3D airfoil aerodynamic efficiency improvement. |