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Numerical method for tracking the multi-media interface between compressible gas and incompressible liquid

A multi-media interface and compressed liquid technology, applied in the direction of electrical digital data processing, special data processing applications, instruments, etc., can solve problems such as difficult to adapt to multi-media problems and variable time steps, to achieve improved accuracy, simple programming, and calculation high efficiency effect

Active Publication Date: 2018-08-28
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Problems solved by technology

At the same time, because the time step of the existing incompressible DG method is uniform and constant, it is often difficult to adapt to the requirements of variable time steps in multi-media problems, so the present invention derives an incompressible time discrete format based on non-uniform time steps

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  • Numerical method for tracking the multi-media interface between compressible gas and incompressible liquid
  • Numerical method for tracking the multi-media interface between compressible gas and incompressible liquid
  • Numerical method for tracking the multi-media interface between compressible gas and incompressible liquid

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Embodiment Construction

[0076] The content of the invention will be further described below in conjunction with the accompanying drawings and calculation examples.

[0077] (1) Control equation

[0078] The governing equation for a compressible gas is the Euler equation:

[0079]

[0080] Where: U=[ρ,ρu,ρv,E] T ,F(U)=[F 1 (U),F 2 (U)], F 1 (U)=[ρu,ρu 2 +p,ρuv,(E+p)u] T ,F 2 (U)=[ρv,ρuv,ρv 2 +p,(E+p)v] T . ρ is the density, u is the velocity in the x direction, v is the velocity in the y direction, p is the pressure, and E is the total energy per unit volume, which is defined as:

[0081] E=ρe+ρ(u 2 +v 2 ) / twenty two)

[0082] where e is the internal energy per unit mass. The state equation is:

[0083] p=(γ-1)ρe (3)

[0084] For an ideal gas γ is the specific heat ratio.

[0085] The governing equation for an incompressible liquid is the Navier-Stokes equation:

[0086]

[0087]

[0088] Among them, V=(u,v) is the velocity vector, μ is the viscosity coefficient. ρ and μ ...

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Abstract

The present invention discloses a compressible gas and incompressible liquid multimedia interface tracking numerical method. Single gas and fluid medium regions both adopt discontinuity galerkin method for calculation, and due to non-uniformity variation of time step length of a multimedia flow field, the method disclosed by the present invention induces a time discretization format based non-uniformity time step length when solving an incompressible Navier-Stokers equation by adopting the discontinuity galerkin method. A multimedia interface boundary condition is defined by adopting a modified virtual fluid method. A new compressible and incompressible riemann problem is constructed in a normal direction in a stuff interface to predict an interface state, and the predicted interface state is not only used for pushing a multimedia interface, but also can directly update a density on one side of compressible gas near the interface and obtain a corresponding virtual fluid state by extrapolation. By verification of multiple classic numerical calculation examples, it is found that the method is capable of obtaining a more accurate numerical simulation result for a multimedia problem of shock-waves appearing in gas.

Description

Technical field: [0001] The invention relates to a numerical method for tracking a compressible gas and an incompressible liquid multi-media interface, which belongs to the fields of computational fluid dynamics and multiphase flow numerical simulation. Background technique: [0002] Due to the large difference in the material properties of compressible gas and incompressible liquid, it is difficult to numerically simulate related gas-liquid multi-media problems. In the early studies, both gas and liquid were used as compressible media to reduce the difficulty of calculation, and the state equation of the liquid was Tait's equation. However, due to the large difference in material properties on both sides of the interface, non-physical oscillations are easy to occur at the material interface, and the calculation time step is too small due to the high sound velocity in the liquid, which reduces the calculation efficiency. When both gas and liquid are used as incompressible m...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F19/00
CPCG16Z99/00
Inventor 卢海天赵宁朱君
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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