American author Michael James Young wrote a paper titled "Derivation of Special Relativity from Subsonic Compressible Aerodynamics". This article by American friend Michael James Young, about the idea of ​​deriving special relativity from subsonic compressible aerodynamics, refers to my 2002 paper and Hu Changwei's 2014 book, and it is more detailed than what I wrote, so I am very interested in this article. I hereby translate and introduce it to you.

He transforms the convective wave eqation in subsonic compressible flow into a mathematical transformation based on the convective wave equation of incompressible flow. This has far-reaching significance for understanding the physical basis of the transformation used in special relativity.

At the beginning of the article, he briefly reviewed the evolution of using incompressible flow solutions for airfoil design instead of high-speed wind tunnel tests. This in turn led him to introduce the history of aerodynamicists using the Prandtl-Groult space contraction method to replace compressibility effects before World War II. In fact, he did not know that even in modern times, the design of our subsonic aircraft, especially drones, is basically based on low-speed wind tunnel experiments, and these transformations are still in use. And there are new revisions.

The key is that later in the article he deduces that the matrix expressions for relativistic velocity, acceleration, and mass can be derived without Einstein's conjecture or so-called metric invariance, and that these same matrix expressions can be derived from compressible and incompressible flow systems. In theory, considering a linear transformation between a fixed vehicle and a fixed spatial coordinate reference system can develop the same relativistic expressions. The mathematical intersection of special relativity and compressible flow theory is not generally understood or appreciated by physicists and electromagnetic field experts outside the field of subsonic aerodynamics, so it will become an increasingly attractive topic for us to explore. The author's ideas in this regard are quite impressive, although non-mainstream.

In particular, he mentions that the use of distance and time measurement devices may confuse the use and interpretation of coordinate transformations because these devices are also affected by the compressibility of the medium itself. If an acoustic timing device is used in an aircraft connected to external conditions, its time delay measurement will also be affected by the change in air compressibility when the speed changes. Therefore, if the hypothesis that speed affects air compressibility is rejected, then the difference in the time delay measurement of the acoustic device will be wrongly interpreted as a distortion of the space and time coordinates. This is exactly the same space-time distortion that modern physicists are so fond of.

The author, like me, has used derivation to show that the Lorentz factor is not special in the usual sense. Instead, it is a compressibility correction factor that arises from ignoring compressibility in the formulation of the convective wave equation. When compressibility is ignored, the correction factor is needed to compensate for the mathematical artifacts caused by the contraction of space and the dilation of time. If this law is applied to the medium in which light propagates, and it is admitted that the light medium is compressible, then under the assumption that the speed of light is infinite and cannot be exceeded, this transformation must be sacrificed, and the core of this transformation is the Lorentz factor.

The author mentions that the difference between the development of aerodynamic and physical theories is that most aerodynamicists accepted the concept of air compressibility, but most physicists rejected the concept of vacuum compressibility. The twelve coordinate transformations, plus the formulas for subsonic speed, acceleration, and mass were derived entirely by a brute force iterative procedure that exploits the mathematical features of the partial differential equations for compressible flow and its transformation to incompressible flow in classical fluid dynamics. This argument, which I also made by computer derivation thirty years ago, although I only did it in two dimensions and did not have the mathematical derivation of the twelve sets of transformations that the author has now done in three dimensions, still illustrates the point. That is, it also shows that it is not necessary to introduce additional assumptions about positioning and timing between clocks, chord lengths, and acceleration planes.

In summary, I agree with the author's statement that the coordinate transformation, velocity addition, and mass equations for subsonic conditions are examined and found to be mathematically identical to the equations used in special relativity to describe the motion of electromagnetic waves or particles, with the speed of light in a vacuum replacing the speed of sound in air. The convective wave equations for compressible flow and the wave equations of special relativity are completely matched only when the equations of special relativity are assumed to be based on vacuum conditions, where the vacuum is represented by an incompressible flow system with a fixed spatial reference system (IS). The correct starting form for using the convective wave equation is the one that includes time and space cross derivatives. Any mathematical transformation that removes these cross derivatives will convert the resulting equations into a non-physical form representing a fictitious fluid.

他的原始文章

从亚音速可压缩空气动力学理论推导狭义相对论.pdf

如果以上链接下载失效，

也可从他本人链接下载:

http://www.sapub.org/global/showpaperpdf.aspx?doi=10.5923/j.ijtmp.20170705.02

或者和作者本人索取：michael.ungs@tetratech.com，

也可以在评论中给出联系方式和我索取：yangxintie@126.com参考