Triple Hill’s Vortex Synthetic Eddy Method

The generation of initial or inflow synthetic turbulent velocity or scalar fields reproducing statistical characteristics of realistic turbulence is still a challenge. The synthetic eddy method, previously introduced in the context of inflow conditions for large eddy simulations, is based on the ass...

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Bibliographic Details
Published in:Flow, turbulence and combustion turbulence and combustion, 2022-03, Vol.108 (3), p.627-659
Main Authors: Haywood, John S., Sescu, Adrian, Bhushan, Shanti, Kees, Christopher E.
Format: Article
Language:English
Subjects:
Automotive Engineering
Channel flow
Engineering
Engineering Fluid Dynamics
Engineering Thermodynamics
Fluid flow
Fluid- and Aerodynamics
Heat and Mass Transfer
Incompressibility
Inflow
Large eddy simulation
Mathematical analysis
Reynolds stress
Scalars
Tensors
Turbulence
Turbulent flow
Velocity
Velocity distribution
Vortices
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Summary:The generation of initial or inflow synthetic turbulent velocity or scalar fields reproducing statistical characteristics of realistic turbulence is still a challenge. The synthetic eddy method, previously introduced in the context of inflow conditions for large eddy simulations, is based on the assumption that turbulence can be regarded as a superposition of coherent structures. In this paper, a new type of synthetic eddy method is proposed, where the fundamental eddy is constructed by superposing three Hill’s vortices, with their axes orthogonal to each other. A distribution of Hill’s vortices is used to synthesize an anisotropic turbulent velocity field that satisfies the incompressibility condition and match a given Reynolds stress tensor. The amplitudes of the three vortices that form the fundamental eddy are calculated from known Reynolds stress profiles through a transformation from the physical reference frame to the principal-axis reference frame. In this way, divergence-free anisotropic turbulent velocity fields are obtained that can reproduce a given Reynolds stress tensor. The model was tested on both isotropic and anisotropic turbulent velocity fields, in the framework of grid turbulence decay and turbulent channel flow, respectively. The transition from artificial to realistic turbulence in the proximity to the inflow boundary was found to be small in all test cases that were considered.
ISSN:1386-6184
1573-1987
DOI:10.1007/s10494-021-00289-4