Laminar–turbulent transition in the boundary layer over a parabolic profile of a straight wing with a relative thickness of 10% is investigated. Freestream conditions correspond to the standard atmosphere at an altitude of 20 km and a Mach number of 3. Disturbances are introduced by a continuously operating blowing–suction actuator, which generates a relatively narrow initial frequency–wavenumber spectrum of perturbations. Direct numerical simulation is performed by solving the full unsteady compressible Navier–Stokes equations for a perfect gas. An analysis of mass-flux perturbations and their frequency–wavenumber spectra is carried out at various streamwise distances from the disturbance generator. The spatial distribution of the coherence function is presented.
Egorov et al. (Wed,) studied this question.