Viscous Flows and Boundary Layers

The viscous flow and boundary layer course is of fundamental importance for any student interested in aerodynamics, renewable energy systems such as wind turbines and hydropower, as well as any applications of fluid flow in mechanical or aeronautical engineering in general. This course provides a more in-depth introduction to viscous flow beginning with exact solutions for flows where viscosity dominates (low Reynolds number) followed by laminar boundary layer theory. The latter part of the course introduces turbulent flow which occurs at higher Reynolds number. The course covers the following topics: Fluid properties and the equations of motion for basics of viscous flows, (Couette, Poiseuille, Combined Couette-poiseulle flows), stresses in a viscous fluid, Navier Stokes equation, laminar boundary layer theory, boundary layer equations, momentum integral equation, similarity solutions, effect of pressure gradients (flow separation), transition to turbulence and turbulent boundary layers.

The course provides the student with knowledge about boundary layer flows around bodies and internal flows which are the building blocks to a wide range of important mechanical and aeronautical engineering problems such as the origin of drag forces in aerodynamics and renewable energy applications such as wind turbines. Students will be able to:

• Formulate and solve problems in fluid mechanics where viscous effects are important.
• Apply and modify the boundary layer equations to account for pressure gradient effects and understand when such approaches are valid.
• Understand similarity solutions, the effect of pressure gradients on the flow, and the origin of drag.
• Apply approximate methods to solve for the boundary layer profile in flows with arbitrary pressure gradients typical of flows around aerofoils.
• Understand the basic concepts behind laminar to turbulent transition, the Reynolds decomposition and turbulent boundary layers.
• Calculate critical parameters like the friction factor, shape factor, boundary layer thicknesses, as well as the mean velocity profile for laminar and turbulent boundary layers over simple geometries.

The lectures and exam will be in English.