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RANS/LES method based on tubulence energy and turbulence length scale truncation

A length-scale, turbulent kinetic energy technology, applied in the field of RANS/LES, which can solve problems such as difficulty in simulating flow structure and poor RANS performance

Inactive Publication Date: 2017-05-17
SOUTH CHINA UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] The RANS method occupies a dominant position in the field of engineering simulation and is widely used. However, for complex flows, such as separation and reattachment flows, RANS performs relatively poorly, and it is difficult to simulate the dominant flow structure.

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  • RANS/LES method based on tubulence energy and turbulence length scale truncation
  • RANS/LES method based on tubulence energy and turbulence length scale truncation
  • RANS/LES method based on tubulence energy and turbulence length scale truncation

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Embodiment Construction

[0050] Combine below Figures 1 to 5 And embodiment the present invention is described in further detail.

[0051] Fully developed turbulent flow in a flat channel is a benchmark case for validating the turbulence model.

[0052] In order to verify the correctness of the present invention, the results of the turbulence model are compared with the simulation results of DNS. details as follows:

[0053] figure 1is the calculation area, that is, the schematic diagram of the flat channel, the dimensions are x=3.2δ, y=2δ, z=1.6δ, the x direction is the flow direction, y is the direction vertical to the wall, and z is the span direction. The number of grids is 35×70×35, the flow direction and the span direction are averagely discrete, the vertical wall direction, the first grid point close to the wall is set at y + = 1.0. Table 1. Characteristic parameters of fluid flow.

[0054] Table 1 flow parameters

[0055]

[0056] To solve equations (1)(2)(3)(4)(13), the equations a...

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Abstract

The invention discloses a RANS / LES method based on tubulence energy and turbulence length scale truncation. The method mainly establishes a novel truncation formula Fr of turbulent viscosity coefficient, and the truncation turbulent viscosity coefficient is obtained. Fr=1, calculation shows RANS; 0<Fr<1, a LES-like model is shown. According to the definition of molecular viscosity coefficient and the turbulence length scale energy spectrum which meets the formula ( the formula is shown in the description.), a Fr calculation formula is deduced. By the combination of a standard K-< model, the RANS / LES method can be achieved. In this way, the method can calculate velocity pulsation at the condition of less grids, and the obtained average velocity comparatively accords with a DNS result.

Description

technical field [0001] The invention relates to the field of fluid mechanics (Computational Fluid Dynamics, CFD), in particular to a RANS / LES method based on turbulent kinetic energy and turbulent length scale truncation. It solves the RANS equation in the near-wall region and presents a turbulence model similar to LES calculation in the far-wall region. Background technique [0002] Turbulent flow exists widely in the fields of nature and engineering, such as the flow of the atmosphere, ocean and waterfalls, the flow of fluid near aircraft wings and hulls, and the flow in fluid machinery are all turbulent flows. Turbulent flow is a very complex multi-scale random and irregular flow, and the study of turbulent flow is of great significance for the prediction of atmospheric environment, the force analysis around aircraft wings and hulls, and the mechanical strength analysis of fluid machinery. Since the analytical solution of the Navier-Stokes equation describing the conserv...

Claims

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Application Information

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IPC IPC(8): G06F19/00
CPCG16Z99/00
Inventor 汪双凤丁普贤
Owner SOUTH CHINA UNIV OF TECH
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