Generation of Taylor-Goertler vortices in decaying swirl flow

The boundary layer instability forming Taylor-Goertler vortices in decaying swirl flow inside a cylinder is studied both experimentally and numerically for Re = 800-10,000. Flow visualization shows four instability regimes: noncell, regular cell, irregular cell, and turbulent cell states. The transition time of these states is estimated, and an expression is derived for the growth of the boundary layer thickness in the regular and irregular cells. The numerical computation of the Navier-Stokes equations reveals the appearance of cellular vortices on the concave wall of the cylinder. Calculated results agree well with experimental data.