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arXiv 2406.06256physics.flu-dynphysics.plasm-ph
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受差分旋转作用的开尔文-亥姆霍兹剪切流研究

Study on Kelvin Helmholtz shear flows subjected to differential rotation

Prince Kumar, Devendra Sharma

AI总结:

本文通过伪谱数值模拟,利用旋转与磁场的类比,研究科里奥利力对开尔文-亥姆霍兹不稳定性的抑制作用,发现其抑制长波长扰动并导致涡旋数量增多。

摘要:

本文采用伪谱方法,对受到外部旋转作用的平行剪切流中的开尔文-亥姆霍兹不稳定性(KHI)进行了数值模拟。在β平面近似下的旋转参考系中产生的科里奥利力,倾向于抑制KHI模式的增长。数值结果与针对阶跃型剪切流剖面所得到的解析结果在定性上高度一致。实验证据表明,旋转参考系中的粒子会受到科里奥利力的作用,该力在数学上等价于洛伦兹力。因此,科里奥利力对流体动力学的影响方式,与磁化剪切流中洛伦兹力的作用方式相似。本文利用磁场与旋转之间的类比关系,研究了在旋转参考系中与磁场等效的效应对KHI的影响。与磁场情形类似,科里奥利力会抑制KHI,并倾向于形成被压缩和拉长的KH涡旋结构。然而,磁场与科里奥利力作用的尺度不同,后者主要抑制长波长模式的扰动。与非旋转情形相比,在存在旋转的情况下可以观察到更多的涡旋。

英文摘要:

A numerical simulation of Kelvin-Helmholtz Instability (KHI) in parallel shear flows subjected to external rotation is carried out using a pseudo-spectral technique. The Coriolis force, arising in a rotation frame under the beta plane approximation, tends to suppress the growth of KHI modes. The numerical results show a close qualitative agreement with the analytical results obtained for a step-wise shear flow profile. Experimental evidence demonstrates that particles in a rotating frame experience the Coriolis force, mathematically equivalent to the Lorentz force. Therefore, the Coriolis force affects fluid dynamics in a manner similar to the Lorentz force in magnetized shear flows. This paper exploits the analogy between the magnetic field and rotation to study effects equivalent to a magnetic field on KHI in a rotating frame. Similar to the magnetic field case, the Coriolis force suppresses KHI and tends to form compressed and elongated KH vortex structures. However, the magnetic field and Coriolis force act on different scales, with the latter suppressing long-wavelength mode perturbations. A higher number of vortices are observed in the presence of rotation compared to non-rotating cases

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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