Understanding inhomogeneous and anisotropic fluid flows requires mathematical and computational tools that are tailored to such flows and distinct from methods used to understand the canonical problem of homogeneous and isotropic turbulence. We review some recent developments in the theory of inhomogeneous and anisotropic turbulence, placing special emphasis on several kinds of quasi-linear approximations and their corresponding statistical formulations. Aspects of quasi-linear theory that have received insufficient attention in the literature are discussed, and open questions are framed.

中文翻译：

---

非均匀和各向异性湍流理论的最新进展


理解非均匀和各向异性流体流动需要针对此类流动定制的数学和计算工具，并且与用于理解均匀和各向同性湍流的典型问题的方法不同。我们回顾了非均匀和各向异性湍流理论的一些最新发展，特别强调了几种拟线性近似及其相应的统计公式。讨论了拟线性理论在文献中没有受到足够重视的方面，并提出了一些悬而未决的问题。