定常升阻力普适理论的特色和升力的物理来源

现代空气动力学诞生一百多年来,己经发展出众多关于升力和阻力的理论.但是,其远场合力理论一直停留在低速不可压流.虽经几代人的努力,但仍未能把它精确地推广到黏性可压缩流.这种状况直到最近才得以突破.本文作者及其合作者依据对远场线化Navier-Stokes方程解析解的研究,获得了经典不可压二维定常流的Kutta-Jouko...

The universal steady lift and drag theory and the physical origin of lift

Since the birth of modern aerodynamics, various theories on lift and drag have been developed and validated extensively in aeronautical applications. However, the far-field force theory had long remained at low-speed incompressible flow. Based on the analytical solutions of the linearized Navier-Stokes equations in the steady far field, the authors and their collaborators extended the classic Kutta-Joukowski lift theorem to both two- and three-dimensional viscous and compressible flows, and thus filled the long-standing gap in theoretical aerodynamics. Why can the simple formulas based on linearized approximation still be accurately valid for highly nonlinear complex flows? This issue of great interest involves the methodological characteristics and physical mechanism behind the unified force theory and is the first task of this article. Moreover, there has been an abnormal phenomenon regarding the physical origin of lift that, despite the already mature and fully verified rigorous lift theory, various different hypotheses still keep surfacing frequently in various nonscientific publications and media. This indicates that the issue is really complicated and has not been thoroughly clarified in textbooks, monographs, and classrooms around the world. Now, the universality and high conciseness of the unified theory enable one to reach a clear answer to this issue by rigorous logical arguments in the most direct way. This is the second task of this article.