Boundary Layer Theory - External Flows Without Surfaces - IX

Explore boundary layer theory applications in fluid dynamics scenarios where solid boundaries are absent through this 54-minute lecture. Begin by examining various flow situations where boundary layer principles still apply despite the lack of physical surfaces. Apply the boundary layer framework to analyze how ambient fluid becomes entrained by a two-dimensional planar jet, deriving a self-similar velocity profile in the downstream region that parallels the Blasius solution found in wall-bounded flows. Discover how the jet's momentum flux remains conserved in the streamwise direction through mathematical analysis. Conclude by investigating a geophysical flow phenomenon where viscous forces balance with Coriolis forces, resulting in the formation of an Ekman spiral—a distinctive velocity profile that changes with depth beneath the ocean surface, demonstrating the broader applications of boundary layer theory in atmospheric and oceanic fluid mechanics.