Nonlinear development and secondary instability of traveling crossflow vortices

Fei Li, Meelan M. Choudhari, Lian Duan, Chau-Lyan Chang
2014 Physics of Fluids  
Building upon the prior research targeting the laminar breakdown mechanisms associated with stationary crossflow instability over a swept-wing configuration, this paper investigates the secondary instability of traveling crossflow modes as an alternate scenario for transition. For the parameter range investigated herein, this alternate scenario is shown to be viable unless the initial amplitudes of the traveling crossflow instability are lower than those of the stationary modes by considerably
more » ... ore than one order of magnitude. The linear growth predictions based on the secondary instability theory are found to agree well with both parabolized stability equations and direct numerical simulation, and the most significant discrepancies among the various predictions are limited to spatial regions of relatively weak secondary growth, i.e., regions where the primary disturbance amplitudes are smaller in comparison to their peak values. Nonlinear effects on secondary instability evolution are also investigated and found to be initially stabilizing when they first come into play. Li et al. Phys. Fluids 26, 064104 (2014) 064104-3 Li et al. Phys. Fluids 26, 064104 (2014) 064104-4 Li et al. Phys. Fluids 26, 064104 (2014) 064104-7 Li et al.
doi:10.1063/1.4883256 fatcat:jv3z2hcxfve5fl7hkjnbsufb5y