A serrated, self-adhesive tape called "Turbulator" is used to change/improve a laminated airflow (over a wing surface for example) into a more controlled turbulent airflow. An induced turbulent airflow can be desired when you get separation bubbles in the boundary layer that is closest to the surface. These separation bubbles that are below the separated airflow creates drag and it's these bubbles that can be made smaller or even disappear completely with the help of the Turbulator tape.
Width: 8.5 mm
Mostly used on sail planes with wings that have low Reynold Numbers and/or on the tail
The small increase in drag created by the Turbulator Tape in higher speeds is minor compared with the large improvement of glide speed
Where to Put the Turbulator Tape? Common wisdom says to locate the leading edge of the turbulator 12 mm in front of the bubble. But the bubble does not have a definite leading edge. It begins separating very early and gradually moves away from the surface. Also, the separation and reattachment points move with airspeed, as indicated in the wing tunnel simulations.
What are the penalties for getting it wrong? If the turbulator is too far to the rear, then at high speeds (bubble forward on lower surface) the bubble may form over or ahead of the tape, resulting in no effect or additional drag without benefits. If the turbulator is too far forward, then the transition to turbulent flow (no bubble) occurs farther forward than necessary and there is a net reduction in the laminar flow area on the wing.
More information about Turbulators can be read here.