Grid structure generation method for fixation of outer boundary

A technology of outer boundaries and moving grids, applied in special data processing applications, instruments, electrical digital data processing, etc., can solve problems such as grid distortion, difficult processing of moving far-field boundaries, negative volume, etc.

Inactive Publication Date: 2016-08-10
BEIJING LINJIN SPACE AIRCRAFT SYST ENG INST +1
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Problems solved by technology

The former grid is rigidly connected to the object surface and moves with the object without changing the shape of the grid. This method is simple and is suitable for any shape and any movement. The grid quality is good and fully conforms to the geometric conservation rate. The movement of the body makes the displacement and velocity of the far-field boundary very lar

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  • Grid structure generation method for fixation of outer boundary
  • Grid structure generation method for fixation of outer boundary
  • Grid structure generation method for fixation of outer boundary

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[0056] The present invention will be described in detail below with reference to the drawings and specific embodiments.

[0057] The method for generating a structured dynamic grid with a fixed outer boundary of the present invention includes the following steps:

[0058] 1. Generate the initial grid and divide the initial grid into two intervals of the inner field and the outer field, see figure 1 , Where s1 is the internal field, s2 is the external field, and ξ and η are the two coordinate symbols of the two-dimensional curvilinear coordinate system. Due to the popularity of grid generation software, the initial grid is generally generated by Gridgen / Pointwise, ICEM and other engineering software. Take NACA0012 airfoil as an example, the initial grid generated by Gridgen software is shown in Figure 4 .

[0059] The initial grid should ensure good orthogonality and smooth transition characteristics, while ensuring that the size of the external field meets the CFD calculation requi...

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Abstract

The invention belongs to the technical field of CFD grid generation, in particular to a grid structure generation method used for forced oscillation and six-degree-of-freedom freely-flying CFD calculations.The method comprises following steps: (1) generating an initial grid and dividing the initial grid into two sections including an inner boundary and an outer boundary; (2) solving a source item of the initial grid; (3) rotating the inner-boundary grid, designating a rotary axis and a rotation angle in order to obtain the internal grid in the new state; and (4) solving a grid for the smooth outer boundary of an elliptical equation.The grid structure generation method for fixation of the outer boundary has following beneficial effects: the grid generated by the invention keeps the outer boundary stationary and ensures features such as orthogonality and normal height of the grid at the wall surface; the outer-boundary grid demonstrates smooth quality by solving the elliptical equation; and the grid quality can be ensured after large-angle rotation.

Description

technical field [0001] The invention belongs to the technical field of CFD grid generation, and in particular relates to a structural dynamic grid generation method that can be used for forced oscillation and six-degree-of-freedom CFD calculation. Background technique [0002] In recent years, with the advancement of technology and the upgrading of aircraft performance requirements, the research on the aerodynamic characteristics of aircraft based on unsteady flow has become more and more a hot spot, and forced motion and free flight are important ways to study the unsteady aerodynamic characteristics of aircraft. With the rapid development of computer technology and numerical calculation methods, CFD has become an effective way to solve the above unsteady problems. To use CFD to calculate unsteady dynamic characteristics, the problem of mesh motion must be solved first. [0003] There are two main methods for generating structural dynamic meshes: rigid rotation method and o...

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Application Information

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IPC IPC(8): G06F17/50
Inventor 苗萌卢凤翎周禹闵昌万
Owner BEIJING LINJIN SPACE AIRCRAFT SYST ENG INST
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