Modern Fluid Dynamics as Pseudo-Science?

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A common feature of pseudo-science is theory claiming a substantial effect from a small or unknown cause making experimental testing impossible. Let us subject modern fluid dynamics to this test.

Modern fluid and aerodynamics is dominated by Ludwig Prandtl named Father of modern fluid mechanics and Zhukovsky named Father of Russian aerodynamics supported by his German homolog Wilhelm Kutta.

Prandtl developed boundary layer theory to explain substantial drag of a bluff body in a fluid with small viscosity and Kutta-Zhukovsky circulation theory to explain large lift of a wing. Prandtl claimed that substantial drag originates from a vanishingly thin boundary layer and Kutta-Zhukovsky that large lift originates from a sharp trailing edge singularity. In both cases a substantial effect is claimed to come from a small or unknown cause.

I leave the conclusion to the reader.

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  1. liquifun

    While reading this article, a story from Richard Feynman popped into my head. Once in an interview he said that if alien civilizations would have existed and they would have come to visit the Earth, they could have made very strange theories. For example: there is a line on the surface of the Earth which is constantly moving from east to west, indicating the boundary of day and night. And if they would examine the behavior of people along that line, they would see that the humans are putting strange plastic sticks in their mouth and start brushing their teeth. From this, they would conclude that wherever the boundary of day and night is, the presence of this boundary makes the humans brush their teeth. Of course we know that cleaning our teeth is not because dusk or dawn, but because we want them to remain healthy as long as possible by cleaning it twice a day – morning and evening.

    What I want to say is that a theory explaining a phenomenon and its causes may sound very firm first, but a closer look (if possible) can reveal that it may not be the full explanation.

    I think the theories mentioned in the article are in some sense the same – they proved to be useful in the practical sense (after all we could design planes that didn’t fall down the sky) but they do not cover the “whole story”. It does not mean that they are bad, only indicates that there are boundaries to their applications.

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