The stabilizing effect of streaks on TS and oblique waves: A parametric study

Authors: Bagheri, S., Hanifi, A.
Document Type: Article
Pubstate: Published
Journal: Phys. Fluids
Volume: 19   078103
Year: 2007


The stabilizing effect of finite amplitude streaks on the linear growth of unstable perturbations (TS and oblique waves) is numerically investigated by means of the nonlinear Parabolized Stability Equations. We have found that for stabilization of a TS-wave, there exists an ``optimal' spanwise spacing of the streaks. These streaks reach their maximum amplitudes close to the first neutral point of the TS-wave and induce the largest distortion of the mean flow in the unstable region of the TS-wave. For a such distribution, the required streak amplitude for complete stabilization of a given TS-wave is considerably lower than for $\beta=0.45$, which is the optimal for streak growth and used in previous studies. We have also observed a damping effect of streaks on the growth rate of oblique waves in Blasius boundary layer and for TS- waves in Falkner-Skan boundary layers.