Characterizing boundary-layer instability at finite Reynolds numbers
The author investigates the stability of adverse pressure gradient boundary layers using Orr-Sommerfeld theory and Falkner-Skan similarity profiles in order to characterize viscous and inviscid instabilities under practical conditions. The results elucidate appropriate scalings of asymptotic large-Reynolds-number theories. In particular, it is shown that viscous instability, usually associated with the lower branch of the neutral curve, extends up to the upper branch of the neutral curve, and is separated from the inviscid instability by a kink in the neutral curve. The rather unexpected conclusion is that, even for relatively strong adverse pressure gradients, the transition seems likely to be driven by an essentially viscous instability mechanism despite the presence of an inflection point.
scientific article; zbMATH DE number 1282951
scientific article