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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 large, which makes it difficult to deal with the moving far-field boundary; , when close to the object surface, the grid weight of the rigid rotation method, this method keeps the outer boundary still, and has good adaptability to complex shapes, but for large-scale movements, mesh distortion and negative volume will appear, such as large angle of attack pitching motion

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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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Embodiment Construction

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

[0057] The method for generating a structural dynamic mesh with a fixed outer boundary according to the present invention includes the following steps:

[0058] 1. Generate the initial grid, and divide the initial grid into two intervals, the inner field and the outer field, see figure 1, where s1 is the inner field, s2 is the outer 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 engineering software such as Gridn / Pointwise and ICEM. Taking the NACA0012 airfoil as an example, the initial grid generated by Gridn software is shown in Figure 4 .

[0059] The initial grid should ensure good orthogonality and smooth transition characteristics, and at the same time ensure that the size of the exter...

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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...

Claims

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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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