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Riemann resolver shock wave instability suppression method and system

An instability and solver technology, applied in sustainable transportation, design optimization/simulation, geometric CAD, etc., can solve problems such as poor versatility, low accuracy and reliability

Active Publication Date: 2020-04-21
NAT UNIV OF DEFENSE TECH
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Problems solved by technology

[0007] The present invention provides a shock wave instability suppression method and system of a Riemann solver, a shock wave simulation method and system, which are used to overcome defects such as low precision and reliability and poor versatility in the prior art. When different types of Riemann solvers are used in combination, the effective shock wave detection method can be used to change the dissipation of the solver in different regions, reduce the impact on the accuracy of numerical simulation, and improve the reliability and versatility of calculations

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  • Riemann resolver shock wave instability suppression method and system
  • Riemann resolver shock wave instability suppression method and system
  • Riemann resolver shock wave instability suppression method and system

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Embodiment 1

[0036] as attached Figure 1-4 As shown, the embodiment of the present invention provides a method for suppressing shock wave instability of a Riemann solver, including:

[0037] The Navier-Stokes equation discretized by the finite volume method is:

[0038]

[0039] In formula (1), U represents the conserved variable vector in the flow field, Ω represents the volume of the calculation grid, N is the number of grids, ΔS represents the length of the grid interface, and F c with F v represent the convective flux vector and the viscous flux vector respectively, which are functions of the conserved variable U and can be obtained directly from the state variables in the flow field. The convective term in equation (1) is solved by the Riemann solver, usually It can be expressed as:

[0040]

[0041] The usual Riemann solver can be expressed in the form of formula (2). In this formula (2) U L with U R represent the conserved variable vectors on the left and right sides of...

Embodiment 2

[0065] figure 1 The basic flow chart of solving the Navier-Stokes equation using the finite volume scheme of the Riemann solver is given, and the specific implementation is as follows. Include the following steps:

[0066] The flow condition of the compressible flow field is initialized as a variable by using the finite volume method;

[0067] Use the limiter function to reconstruct the initialized variables in the flow field to obtain the flow field variable distribution inside each grid cell;

[0068] Using a Riemann solver to solve the flow field inside the grid unit to obtain the numerical flux function value on the grid interface, that is, the discrete value of the convection term of the Navier-Stokes equation;

[0069] The value of the numerical flux function on the grid interface is updated by the shock wave instability suppression method of the Riemann solver in any embodiment one;

[0070] Determine whether the iteration time reaches the iteration condition, and re...

Embodiment 3

[0076] Based on the first embodiment above, the present invention provides a Riemann solver shock instability suppression system, including a memory and a processor, the memory stores a Riemann solver shock instability suppression program, the The processor executes the steps in any embodiment of the above method when running the Riemann solver shock wave instability suppression program.

[0077] Based on the second embodiment above, the present invention provides a shock wave simulation system based on a Riemann solver, including a memory and a processor, the memory stores a shock wave simulation program based on a Riemann solver, and the processor The steps of any method described in the second embodiment are executed when the shock wave simulation program based on the Riemann solver is run.

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Abstract

The invention discloses a Riemann resolver shock wave instability suppression method and system and a shock wave simulation method and system. The suppression method comprises the steps: constructinga general pressure dissipation function through the product of a pressure weight function and a pressure dissipation function, wherein the pressure weight function value is increased along with the increase of the pressure gradient, and the pressure weight function value is changed between intervals [0, 1]; establishing a relationship between a general pressure dissipation function and a convection term solving result in the Wiener Stokes equation by a general Riemann resolver so as to change the dissipativity of the Riemann resolver in a shock wave region, and activating the pressure dissipation function through a pressure weight function when the Riemann resolver is close to the shock wave region; and when being far away from the shock wave area, closing the pressure dissipation functionthrough the pressure weight function to inhibit the shock wave instability phenomenon. The problems of inaccurate simulation, low calculation reliability and universality and the like in the prior art are solved, the dissipativity of the resolver is changed in different areas, the influence on the numerical simulation precision is reduced, and the calculation reliability and universality are improved.

Description

technical field [0001] The invention relates to the technical field of shock wave suppression, in particular to a shock wave instability suppression method and system for a Riemann solver, and a shock wave simulation method and system. Background technique [0002] With the development of computer technology and the advancement of numerical methods, computational fluid dynamics has made great progress. Due to the long time-consuming and huge cost of ground experiments and flight tests, numerical simulation has increasingly become the main means of aircraft aerodynamic layout design. For the aircraft flying in the adjacent space, due to its high cruising speed and large flight Mach number, the high-speed airflow is often compressed violently to form a shock wave around the aircraft. The appearance of shock waves will seriously affect the aerodynamic performance of the aircraft, thus affecting the layout design and optimization of the aircraft. Therefore, how to accurately s...

Claims

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Application Information

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IPC IPC(8): G06F30/28G06F30/15
CPCY02T90/00
Inventor 谢文佳李桦田正雨
Owner NAT UNIV OF DEFENSE TECH
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