Measurement and Identification of Supersonic Stationary Crossflow Waves Based on Sublimation Method

Aiming at the crossflow transition problem of supersonic swept wings, an experimental study on the measurement and identification of boundary-layer stationary crossflow waves was carried out at Mach number 2.0. A 65 deg straight-swept-wing model with simple airfoil geometry was designed to capture the crossflow transition phenomenon. The sublimation method for a large-scale cold supersonic wind tunnel was developed to acquire a transition pattern. The stationary crossflow wave identification technology is based on image processing, a vertical and horizontal decomposition method is established, and the quantitative characteristic information (such as the vortex axis spacing and direction) can be identified from high-resolution sublimation images. The experimental results show that the transition position caused by crossflow instability is closed to the leading edge for supersonic wings with large sweep angles at high Reynolds numbers, and the transition position moves upstream with the increase of the unit Reynolds number. The identified vortex axis spacing and direction are basically consistent with the linear stability theory. The stationary disturbance wave information at different Reynolds numbers is compared and analyzed. It is found that the unit Reynolds number plays an important role in the selection and amplification of the unstable stationary modes with different wavelengths in the transition process.