We study the shear-driven instability, of Kelvin–Helmholtz type, that forms at the interface between a cylindrical jet of flowing fluid and its surroundings. The results of an infinitesimal-amplitude theory based on linearising the system about the undisturbed jet are given. A novel numerical model based on the Galerkin spectral method is developed and employed to simulate the non-linear development of the jet in the weakly-compressible Boussinesq regime. Representative results demonstrating the viability of this model are given, and are shown to agree with the linear analysis for small disturbances, but to develop cylindrical roll-up in the severely non-linear regime.

中文翻译：

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不可压缩流体轴对称射流的不稳定时间发展

我们研究了在流动流体的圆柱形射流与其周围环境之间的界面处形成的 Kelvin-Helmholtz 型剪切驱动不稳定性。给出了基于对未受干扰射流系统进行线性化的无穷小幅度理论的结果。开发了一种基于伽辽金谱方法的新型数值模型，用于模拟弱可压缩 Boussinesq 区域射流的非线性发展。给出了证明该模型可行性的代表性结果，并表明与小扰动的线性分析一致，但在严重非线性状态下发展圆柱形卷起。