THE FULL LIFESPAN OF THE BOUNDARY-LAYER AND MIXING-LENGTH CONCEPTS

摘要

Ludwig Prandtl's most penetrating contributions are approximations to thedynamics of fluids As such, they are liable to be superseded, at the time it becomes possible to solve the original equations analytically or, more probably, to routinely obtain numerical solutions so accurate they solve the problem without explicit use of the approximations. The engineering value of the theories is distinguished from their educational and intuitive value The purpose here is to envision when and how this shift will happen for the boundary-layer and mixing-length concepts, with an aside on lifting-line theory, thus defining in some sense the lifespan of Prandtl's ideas.