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arXiv · 2309.03358

On a 1/2-equation model of turbulence

Rui Fang·Weiwei Han·William Layton
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Abstract

In 1-equation URANS models of turbulence the eddy viscosity is given by $\nu_{T}=0.55l(x,t)\sqrt{k(x,t)}$ . The length scale $l$ must be pre-specified and $k(x,t)$ is determined by solving a nonlinear partial differential equation. We show that in interesting cases the spacial mean of $k(x,t)$ satisfies a simple ordinary differential equation. Using its solution in $\nu_{T}$ results in a 1/2-equation model. This model has attractive analytic properties. Further, in comparative tests in 2d and 3d the velocity statistics produced by the 1/2-equation model are comparable to those of the full 1-equation model.

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Rui Fang, Weiwei Han, William Layton. 2023-09-06. On a 1/2-equation model of turbulence. https://arxiv.org/abs/2309.03358

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