Historical and Classical Works
The history of boundary layer is very rich and interesting. Starting from Prandtl’s original work (1904) and his student Blasius and von Karman and others (in the field of turbulent flows as well), the theory has developed over the years. Many researchers, all over the world, contributed to this subject. In Gottingen, Germany, where Prandtl worked, there was a conference in 2004, celebrating 100 years anniversary of boundary layer theory (the proceedings is published by Springer Verlag ).
In these notes, some topics will be discussed with historical remarks. Transformations of subsonic boundary layer equations to the incompressible ones show that compressibility effects do not change the basic phenomena. Singularities at separation (and attachment) points as well as trailing edge show the limitation of boundary layer equations and the importance of coupling viscous and inviscid flows (as suggested by Prandtl himself through introducing the concept of displacement thickness). Treatment of separated flows is important for practical applications. Axisymmetric flow transformation to 2-D like equations (Mangler) and three dimensional flows over swept wings are also discussed.
Some of these works are of limited values today, thanks to the power of our computers. Nevertheless, it is still useful to study the ideas behind them.