Breakdown of a streak via development of varicose secondary mode on the straight wing with pressure gradient Kozlov, V.V., Chernoray, V.G., Litvinenko, Yu.A., Löfdahl, L. 2006 In Laminar-Turbulent Transition. Proc. of Sixth IUTAM Symposium, Bangalore, India 2004, 419–424, Dec. 13–17 (ed. Govindarajan R.), Springer In the present experimental work, which utilizes a hot-wire visualization method, an influence of external pressure gradient on the development of secondary instabilities in the straight wing boundary layers has been demonstrated for the first time. The comparison of experimental data and direct numerical simulation results of this process has been given.