Numerical method for solving two-dimensional Riemannian problem and simulating subsonic non-viscous stream

A technology of Riemann problem and numerical method, applied in the field of computational fluid dynamics, which can solve problems such as numerical solution errors

Inactive Publication Date: 2013-01-23
TIANJIN AEROCODE ENG APPL SOFTWAREDEV
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  • Abstract
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  • Claims
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Problems solved by technology

Obviously, violating the entropy increase principle of the shock wave will cause a certain error in the numerical solution

Method used

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  • Numerical method for solving two-dimensional Riemannian problem and simulating subsonic non-viscous stream
  • Numerical method for solving two-dimensional Riemannian problem and simulating subsonic non-viscous stream
  • Numerical method for solving two-dimensional Riemannian problem and simulating subsonic non-viscous stream

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Embodiment Construction

[0112] According to the method introduced by the present invention, a complete example of using the Euler equation of the flow function to simulate the flow in an inviscid, subsonic nozzle is given below. Among them, the numerical method for solving the two-dimensional Riemann problem provided by the present invention is used to calculate the flux value of the convection term on the grid boundary. The nozzle in this example is a two-dimensional, parabolic wall, length L, and inlet height H in The expansion nozzle. Its geometric size is defined by two parabolas,

[0113] H ( x ) = - a x 2 , 0 ≤ x L / 2 ; a ( x - L ) 2 - b , L / 2 ≤ x ≤ L , - - - ( 54 )

[0114] Where H in =L / 3, a=H in / 2, b=H in / L. The Mach number of the non-viscous, compressible flow at the nozzle inlet is M in = 0.5. The flow is pure subsonic speed. In the method of solving Euler equatio...

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Abstract

The invention belongs to the field of computational fluid mechanics, in particular to a numerical method for solving a two-dimensional Riemannian problem, and is applied to solve an Euler equation and perform the numerical simulation of subsonic non-viscous stream. By the numerical method, the Euler equation on an Euler plane is transformed to a stream function plane; in a two-dimensional Cartesian grid, the Riemannian problem of a translational stream line and the Riemannian problem along the stream line are solved, so that the error of a numerical solution is reduced.

Description

1. Technical Field [0001] The invention belongs to the field of computational fluid mechanics, and specifically is a numerical method for solving two-dimensional Riemann problems, which is applied to the numerical simulation of subsonic and inviscid flow. 2. Background technology [0002] The Riemann Problem was first proposed in the field of aerodynamics, originally referring to a special flow phenomenon of compressible fluid in a one-dimensional shock tube. Specifically, it means that a compressible fluid, such as air, is compressed in a one-dimensional pipe until a shock wave appears. The appearance of shock waves indicates that the flow of fluid is discontinuous. Across the shock wave, the velocity, density, pressure, and entropy of the fluid all undergo jump changes. In 1858, Riemann studied the characteristics of this discontinuous flow phenomenon, and proposed and solved one of the simplest initial value problems of the one-dimensional Euler equation, which was later cal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F19/00
Inventor 路明
Owner TIANJIN AEROCODE ENG APPL SOFTWAREDEV
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