2born (2born) wrote,
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Об ошибках в объяснении подъемной силы

On the Origins and Relevance of the Equal Transit Time Fallacy to Explain Lift: https://arxiv.org/abs/2110.00690
Graham Wild
Recently, aerodynamics syllabi have changed in high schools, pilot ground training, and even undergraduate physics. In contrast, there has been no change in the basic theory taught to aeronautical or aerospace engineers. What has changed is technology, both experimentally and computationally. The internet and social media have also empowered citizen science such that the deficiencies in the legacy physics education around flight and lift are well known. The long-standing equal transit time (ETT) theory to explain lift has been proven false. If incorrect, why was it ever taught? Through a historical analysis of relevant fluid and aerodynamics literature, this study attempts to explain why ETT theory is part of our collectively lower-level cognitive understanding of lift and flight. It was found that in 1744 D'Alembert himself assumed this to be a feature of moving fluids, and while this initial intuition (ETT 1.0) was incorrect, the property of ETT (ETT 2.0) was derived in 1752 when applying Newton's laws of motion to fluids. This incorrect result was independently confirmed in 1757 by Euler! The conclusion is that an over simplified treatment of fluids predicts ETT, along with no lift and drag. This then leads to the open question, can ETT be taught at an appropriately low level as an explanation for lift?
Comments: 5 pages, 5 figures,
Tags: Мегаучебник или Что я читал и похвалил, разгребая arXiv'ы
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