Investigation of HLFC on swept wing based on sublimation technique

Sublimation flow visualization was used in the experiments conducted in the low-turbulence wind tunnel on a NACA64A-204 swept airfoil. The effect of the hybrid laminar flow control (HLFC) on the transition locations at different suction quantities and different attack angles was experimentally researched. Hot-wire measured streamwise velocity to study the disturbances growth mechanism. The results show that naphthalene sublimation flow visualization is appropriate for studying influence of the HLFC method on swept wing transition. The transition location could be displayed intuitively and accurately on swept wing. When there is no suction, the length of the laminar flow region will be increased first and then decreased with the increasing of the attack angle from -6° to 2°. The HLFC method can remarkably delay the transition caused by crossflow instability. The increase of the suction quantity can effectively reduce the energy of dominated disturbance wave at the same attack angle.