AdvancedTopic 73 of 105Thermodynamics & Fluids
Airfoil aerodynamics
Shape generates lift through pressure difference and circulation.
In depth
Aerofoil shape and angle of attack generate circulation and a pressure difference. Lift coefficient rises about 2π per radian (thin-airfoil theory) until stall near 15°. Parameters: camber, chord, thickness (NACA series), Reynolds number. Wing aspect ratio sets induced drag.
Key points
- Lift-to-drag ratio
- Flaps and slats
- Winglets
ExampleA glider with L/D=40 travels 40 m forward per metre of height lost.
What is Airfoil aerodynamics?
Shape generates lift through pressure difference and circulation.
Why is it important to understand airfoil aerodynamics?
Lift from airfoils keeps aircraft and wind turbines aloft or rotating, so understanding circulation and pressure gives the design basis for both.
How does an airfoil produce lift?
The shape and angle of attack create a pressure difference and circulation, which together produce a net upward force.
What is the Kutta condition?
It states that the flow leaves the trailing edge smoothly, which sets the circulation and therefore the lift of an airfoil.
How is Airfoil aerodynamics used in practice?
Typical applications include designing a wing profile for a light aircraft, choosing the blade shape of a wind turbine for efficient lift and explaining why a sail generates force when the wind blows across it.
What should I learn before Airfoil aerodynamics?
Study "Flow separation" first (topic 72 of 105 in Thermodynamics & Fluids). It covers the groundwork this topic builds on.
What are the key points of Airfoil aerodynamics?
Lift-to-drag ratio. Flaps and slats. Winglets.
Can you give an example of Airfoil aerodynamics?
A glider with L/D=40 travels 40 m forward per metre of height lost.
What comes after Airfoil aerodynamics?
The next topic is "Open channel flow", which builds directly on this one.
How difficult is Airfoil aerodynamics?
It is classed as Advanced in Thermodynamics & Fluids (topic 73 of 105). It is an advanced topic. It assumes you are comfortable with the intermediate topics in Thermodynamics & Fluids.