The present invention provides a system and method for controlling leading
edge contamination and crossflow instabilities for laminar flow on
aircraft airfoils that is lightweight, low power, economical and reliable.
Plasma surface discharges supply volumetric heating of the supersonic
boundary layers to control the Poll Reynolds number and the cross flow
Reynolds number and delay transition to turbulent flow associated with the
leading edge contamination and crossflow instabilities. A closed-loop
feedback control system that incorporates these principles includes three
primary components: heat-flow sensors, a PID controller, and plasma
discharge elements. Heat-flow sensors distributed around the airfoil
surface provide root-mean-square (rms) pulsations of the heat flow to the
airfoil skin. These data are fed to the PID controller to determine the
flow state (laminar or turbulent) and to drive voltage inputs to the
plasma discharge elements, which provide the volumetric heating of the
boundary layer on a time scale necessary to adapt to changing flight
conditions and delay transition to turbulent flow.
