Experimental investigation of HLFC mechanism on swept wing

Hybrid laminar flow control(HLFC) experiments were conducted in the low-turbulence wind tunnel on a NACA64A-204 swept airfoil.Naphthalene sublimation flow visualization technology and hot-wire measurement method were taken to examine the effects of suction quantities on transition location and hydrodynamic stability.Experimental results show that transition location occurs at x/c≈0.4 in the non-suction case,and transition location can reach 80% of chord length(behind the minimum pressure point) in both standard and twice suction quantities.The HLFC methods can reduce the distortion of the velocity profile,bring down the nonlinear interaction among the disturbances,decrease the energy of dominated perturbation,and delay transition to achieve lager laminar flow region.