Comparing the wake behind circular and elliptical cylinders in a uniform current

Yazdi, Mohammad Javad Ezadi; Khoshnevis, Abdolamir Bak

doi:10.1007/s42452-020-2698-z

Cited by 5 publications

(1 citation statement)

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“…Yet, in-depth explorations of accelerated wakes and their complex aerodynamics have been primarily confined to simple flows past isothermal or heated cylinders [33,34,[53][54][55]. Moreover, it is established that the coherent structures in the wake of a sphere differ significantly from those behind other bluff bodies such as circular cylinders, presenting unique challenges and opportunities for detailed flow analysis [56,57]. The literature indicates that various approaches have been considered to capture the unsteadiness of the aerodynamic load on a static sphere, providing reliable correlations to calculate fluid forces and field fluctuations [13,27,58] as well as quantitative measurement of high-order metrics [23,28,59].…”

Section: Introductionmentioning

confidence: 99%

Toward Scale-Adaptive Subgrid-Scale Model in LES for Turbulent Flow Past a Sphere

Marefat,

Alam,

Pope

2024

Fluids

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This study explores the dynamics of turbulent flow around a sphere at a Reynolds number of Re=103 using large-eddy simulation, focusing on the intricate connection between vortices and strain within the recirculation bubble of the wake. Employing a relatively new subgrid-scale modeling approach based on scale adaptivity, this research implements a functional relation to compute ksgs that encompasses both vortex-stretching and strain rate mechanisms essential for the energy cascade process. The effectiveness of this approach is analyzed in the wake of the sphere, particularly in the recirculation bubble, at the specified Reynolds number. It is also evaluated in comparison with two different subgrid-scale models through detailed analysis of the coherent structures within the recirculation bubble. These models—scale-adaptive, k-Equation, and dynamic k-Equation—are assessed for their ability to capture the complex flow dynamics near the wake. The findings indicate that while all models proficiently simulate key turbulent wake features such as vortex formation and kinetic energy distribution, they exhibit unique strengths and limitations in depicting specific flow characteristics. The scale-adaptive model shows a good ability to dynamically adjust to local flow conditions, thereby enhancing the representation of turbulent structures and eddy viscosity. Similarly, the dKE model exhibits advantages in energy dissipation and vortex dynamics due to its capability to adjust coefficients dynamically based on local conditions. The comparative analysis and statistical evaluation of vortex stretching and strain across models deepen the understanding of turbulence asymmetries and intensities, providing crucial insights for advancing aerodynamic design and analysis in various engineering fields and laying the groundwork for further sophisticated turbulence modeling explorations.

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