Shear Flows: Instabilities and Waves

This lecture covers the concepts of spatially developing shear flows, including flat plate boundary layers, mixing layers, cylinder wakes, and plane channel flows. It also delves into 2D parallel flow concepts, such as dispersion relations, normal mode decomposition, and the Orr-Sommerfeld equation. The influence of viscosity on Kelvin-Helmholtz instability is discussed, along with viscous instabilities and the hyperbolic tangent mixing layer. The lecture explores the stability of plane Poiseuille flow, the marginal stability curve, and the destabilizing effect of viscosity on boundary layers. Additionally, it examines Tollmien-Schlichting waves, the Orr-Sommerfeld-Squire equation, and the temporal growth rate of boundary layer instabilities.