Stability Criteria and Turbulence Paradox Problem For Type II 3D Shears

Abstract: There are two types of 3D shears in channel flows: ($U(y,z),0,0$) and ($U(y),0,W(y)$). Both are important in organizing the phase space structures of the channel flows. Stability criteria of the type I 3D shears were studied in [Li, 2010]. Here we study the stability criteria of the type II 3D shears. We also provide more support to the idea of resolution of a turbulence paradox, introduced in [Li and Lin, 2010], by studying a sequence of type II 3D shears.