Model of non-stationary, inhomogeneous turbulence

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• 作者：Andrew D. Bragg ; Susan Kurien…
• 关键词：Turbulence modeling ; Inhomogeneous turbulence ; Two ; point modeling ; Turbulent mixing ; Non ; stationary turbulence
• 刊名：Theoretical and Computational Fluid Dynamics
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：31
• 期：1
• 页码：51-66
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Engineering Fluid Dynamics; Classical and Continuum Physics; Computational Science and Engineering;
• 出版者：Springer Berlin Heidelberg
• ISSN：1432-2250
• 卷排序：31

文摘

We compare results from a spectral model for non-stationary, inhomogeneous turbulence (Besnard et al. in Theor Comp Fluid Dyn 8:1–35, 1996) with direct numerical simulation (DNS) data of a shear-free mixing layer (SFML) (Tordella et al. in Phys Rev E 77:016309, 2008). The SFML is used as a test case in which the efficacy of the model closure for the physical-space transport of the fluid velocity field can be tested in a flow with inhomogeneity, without the additional complexity of mean-flow coupling. The model is able to capture certain features of the SFML quite well for intermediate to long times, including the evolution of the mixing-layer width and turbulent kinetic energy. At short-times, and for more sensitive statistics such as the generation of the velocity field anisotropy, the model is less accurate. We propose two possible causes for the discrepancies. The first is the local approximation to the pressure-transport and the second is the a priori spherical averaging used to reduce the dimensionality of the solution space of the model, from wavevector to wavenumber space. DNS data are then used to gauge the relative importance of both possible deficiencies in the model.