Adverse pressure gradient effect on nonlinear varicose instability of a streaky structure in an unswept wing boundary layer Litvinenko, Yu.A., Chernoray, V.G., Kozlov, V.V., Grek, G.R., Löfdahl, L., Chun, H.H. 2005 Physics of Fluids 17, 1–3, American Institute of Physics Inc., Paper no 118106 Nonlinear varicose instability of a streaky structure is experimentally investigated in a wing boundary layer. Spatial evolution of the streaky structure perturbed by high-frequency traveling waves is compared at zero and adverse streamwise pressure gradients. The process of streak multiplication and generation of Λ-shaped vortices is under examination. Results obtained testify to the strong influence of pressure gradient upon the breakdown of the streaky structure due to its varicose instability.   check pdf