Computation Connects Theory and Practice of Fluid Dynamics

The virtual computational wind tunnel bridges the gap between theory and practice of fluid dynamics.

The Epilogue of The Dawn of Fluid Dynamics, commented on in the preceding post, discusses the relation between science and technology, or between theory and practice, with focus on the development of fluid dynamics during the 20th century as the privileged science during two World Wars and Prandtl as the Father of Modern Fluid Mechanics:

• Fluid dynamics benefited from the high expectations with which patrons in government and philanthropic foundations, at the armed forces and in the industry, regarded this science.
• The community of international fluid dynamicists was a mix of practical engineers and academic scientists whose institutional affiliation varied from applied mathematics to mechanical engineering...regarding Prandtl as the founding father of their discipline. G. I- Taylor addressed him as "our chief" who deserved a Nobel Prize.
• Prandtl confessed to a preference to this approach (practice rather than theory): "When faced with problems in mechanics, I slowly became a accustomed to "see" forces and accelerations in the equations or to "sense" then by tactile feeling.
• In this book, we have described to what extent the gap between theory and practice was bridged in the age of Prandtl. Surprisingly, physics showed little interest in fluid dynamics.

The gap between theory and practice in fluid dynamics opened already at the start with d'Alembert's paradox and did not diminish under the influence from Prandtl but only got deeper. 

However, when it is now possible, as we show, to computationally solve the Navier-Stokes equations in direct simulation thus offering a virtual wind tunnel, theory and practice comes together for the first time. In particular the Secret of Flight can be revealed.