Turbulator

A turbulator or turbulence or vortex generator referred to in the aerodynamics a little artificially applied surface disturbance, the laminar boundary layer converted into a turbulent to an impending stall delay. They are mostly found on the top of the wings of smaller aircraft.

effect

Velocity profile over an area around the flow. The arrows indicate the extent of the boundary layer within which the air is accelerated. With turbulators, the boundary layer is significantly thicker than without.

The flow resistance of a body with a laminar boundary layer is lower than in a turbulent one - initially a desirable property. For example, the smooth wings of small aircraft have a laminar flow around them.

As the angle of attack increases, the pressure gradients on the wing increase. They lead to a stall and a sudden decrease in lift. As the graphic shows, the thickness of the turbulent boundary layer is greater than that of a laminar boundary layer (arrows), but the flow velocity increases faster with increasing distance. The higher kinetic energy makes the flow less sensitive to detachment from the wing surface.

Turbulators are small artificially created surface defects. They generate eddies and convert a laminar boundary layer flow into a turbulent one. The flow separation is delayed.

Turbulators consist of transverse rails, small vertical plates or holes. Another way of causing the boundary layer flow to change is the blow-out turbulator. This is a series of fine bores through which air is blown into the boundary layer across the direction of flow.

Turbulators are used, for example, in front of ailerons in gliders and wind turbines.

With the help of surface-integrated bending actuators based on shape memory alloys, adaptive turbulators are now even possible.

More options

In addition to vortex generators, there are other ways to stabilize the flow above the wing or the outer skin:

• Saw tooth (aerodynamics)
• Boundary layer fence
• Sucking off / blowing out the boundary layer
• Strake
• Canard wing

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  Vortex generator at BAE Harrier

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  Astir CS with serrated band on the underside of the wing

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  Turbulator in the shape of a sheet metal angle on the nose of a racing car from 1970

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  Dimples on a golf ball.

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  Vortex generators on the rotor blades of a Nordex N117 wind turbine

Individual evidence

1. ↑ Intelligent material can improve aerodynamics. April 17, 2018, accessed November 22, 2019 .