What is vortex generator

What is a vortex generator?

I will try to explain the physical mechanism and add additional information compared to previous answers.

As previously mentioned, the vortex generator usually takes the form of a plate. This plate creates a small vortex. This vortex is basically an area where the flow rotates around its axis. Basically, this plate draws energy from the flow, which this rotation creates on the flow.

Ok, this rotational flow has energy and when properly aligned it will interact with the boundary layer above the wing to give it further energy. With this additional energy, the boundary layer is more resistant to separation, meaning you can further increase the angle of attack and achieve a higher coefficient of lift for the same wing.

Now comes the why? A vortex generator always creates drag, but it can reduce the aircraft's fuel consumption. How?

Think about the overall design of the aircraft. For a given flight condition, the amount of lift generated can be obtained with a large coefficient of lift times the wing surface area.

Now imagine that we are designing the aircraft and we have found that the condition that measures the required size of the wing, for example the maximum runway length at takeoff, to reduce it you need to create more lift a certain speed. To do this, you can either increase the wing surface area or increase the maximum lift you can get from the wing and you can do this by introducing vortex generators that are intelligently designed for this condition.

Later, a compromise is made between increasing the wing surface area (with the influence of air resistance and weight) and including the vortex generators. Although adding these vortex generators increases drag compared to a clean wing, there are times when you actually lower fuel consumption as the other alternative is to add more wing surface and the optimal solution became the vortex generators.

There are several positions of vortex generators, some in the vertical plane to improve rudder efficiency, others in the upper surface of the wing, others above the engine that affects the fin during takeoff or landing.

Another use of Vortex is to design the aircraft as a quick fix to solving "unexpected problems".