Vortex generators and its significance

In aviation or more specifically in aerodynamics we prefer a laminar flow instead of a turbulent flow with lots of vortices in it. But there are cases where vortex is induced intentionally! This is done by vortex generators.

 

Video Credits: Samm Sheperd

 

Vortex generator is an aerodynamic device, as the name suggests vortex generators, generate vortex when attached to an aerodynamic surface. So what is the benefit of generating vortex? Why are vortex generators used?

Do you know airflow cannot be be continuously attached to a surface i.e. the flow gets separated with distance when moving along a surface, this phenomenon is called as boundary layer separation.

As the flow gets separated from the surface, mainly in case of airplane wing it causes control surface inefficiencies which makes the airplane less controllable.

There is another negative impact caused due to flow separation i.e. aerodynamic stall, a condition which makes the wing incapable of generating required lift. 

By using a vortex generator the problem of boundary layer separation can be countered. The vortex generator is placed in the upstream at an oblique angle to the airflow above a wing or a body. 

As the airplane moves vortex is generated behind the vortex generator which reattaches flow to the surface thus delaying flow separation and avoiding aerodynamic stall and ensuring control surface effectiveness.