Effect of riblets on nonlinear disturbances in the boundary layer Chernorai, V.G., Kozlov, V.V., Loefdahl, L., Grek, G.R., Chun H.H. 2006 Thermophysics and Aeromechanics 13 (1), 67–74, MAIK Nauka/Interperiodica Publishing Results of experimental investigations of the nonlinear stage of sinusoidal and varicose instability of a streaky structure, which leads to multiplication of streaky structures and origination of coherent structures (such as Λ-structures), are presented. Riblets suppress the intensity of streaky structures, stabilize the flow against the development of the secondary high-frequency instability of streaky structures, and, for this reason, delay spatial turbulization of the flow. The results of these investigations can be useful for understanding the flow structure in such situations and for possible controlling of the coherent structures aimed at flow stabilization   check pdf