This paper deals with the dynamics of cylindrical collapse with anisotropic fluid distribution in the framework of f(ℛ,𝒯μν𝒯μν) gravity. For this purpose, we consider non-static and static cylindrical spacetimes in the inner and outer regions of a star, respectively. To match both geometries at the hypersurface, we consider the Darmois junction conditions. We use the Misner–Sharp technique to examine the impacts of correction terms and effective fluid parameters on the dynamics of a cylindrical star. A correlation between the Weyl tensor and physical quantities is also developed. The conformally flat condition is not obtained due to the influence of anisotropic pressure and higher-order nonlinear terms. Further, we assume isotropic fluid and specific model of this theory which yields the conformally flat spacetime and inhomogeneous energy density. We conclude that the collapse rate reduces as compared to general relativity due to the inclusion of effective pressure and additional terms of this theory.

中文翻译：

---

f(ℛ,𝒯μν𝒯μν)理论中的恒星结构研究

本文在以下框架中讨论了具有各向异性流体分布的圆柱体坍塌动力学。F(ℛ,𝒯μν𝒯μν)重力。为此，我们分别考虑恒星内部和外部区域的非静态和静态圆柱时空。为了匹配超曲面上的两个几何形状，我们考虑了 Darmois 结条件。我们使用 Misner-Sharp 技术来检查校正项和有效流体参数对圆柱星动力学的影响。外尔张量和物理量之间的相关性也得到了发展。由于各向异性压力和高阶非线性项的影响，无法获得保形平坦条件。此外，我们假设各向同性流体和该理论的特定模型，该模型产生共形平坦的时空和不均匀的能量密度。