| The fluid flows-Gortler vortex flow over a concave surface and axisymmetric far wake--which are dominated by the longitudinal vortices, are chosen to study the effects and the control of the large-scale coherent structures on the laminar-turbulent transition.;In part 2, heat transfer problem of Gortler vortex is considered. This study presents results for ;In part 3, Laminar-turbulent transition of temporally evolving, incompressible, axisymmetric far wake perturbed by two equal and opposite helical modes and one axisymmetric mode has been studied by direct numerical simulations with Fourier spectral and Chebyshev collocation methods. The growth of helical modes is dominant in the linear region, as expected from the linear stability theory. In the fully nonlinear region, the emergence of standing wave mode (0,2) through the nonlinear resonant interactions is found. Nonlinear resonant interaction between (1,1) and (1,;In part I, Spatially developing longitudinal vortices, originating from upstream Gortler vortices, are studied. The behavior of Gortler vortex development from the linear region to the fully nonlinear region was obtained just prior to the development of secondary instabilities and turbulence. Comparison with the experiments are discussed, showing the development of mushroom-like features in the streamwise velocity component. |
