Parametric resonance with a point-vortex pair in a nonstationary deformation flow

► Motion of an arbitrary intensity point-vortex pair in a shear flow is studied. ► Expression for the vorticity center of the pair is reduced to a Riccati equation. ► A parametric resonance leading to unbounded motion of the pair is analyzed. ► An analytical estimate for the main zone in the parametric space is obtained. ► Using numerical calculation, a family of minor zones is obtained.