CN-122020868-A - Aircraft internal and external flow field structure grid division method based on non-matching interface

CN122020868ACN 122020868 ACN122020868 ACN 122020868ACN-122020868-A

Abstract

The application belongs to the field of aerospace and hydrodynamics, and discloses a meshing method of an inner and outer flow field structure of an aircraft based on a non-matching interface, which comprises the steps of decomposing the appearance of the aircraft into two topological subfields of an outer flow field, an air inlet channel and an inner flow field of a tail nozzle, wherein the subfields are connected through a pair of completely coincident interfaces; the internal flow field of the air inlet channel and the external flow field of the tail pipe adopts O-shaped topological structure grids, the external flow field adopts C-shaped topological structure grids, and nodes of the O-shaped topological structure grids and the C-shaped topological structure grids can mutually slide on interfaces. The method solves the problems that in the current complex aircraft appearance internal-external coupling numerical simulation, the non-structural grid has poor adaptability in a near-wall boundary layer area, large calculation amount and difficult full-field conservation and high precision of the mixed grid.

Inventors

Yang Lejie
LI GUOSHUAI
LIU DAWEI
WU JIFEI
QI BIN
LI SHUCHUAN
QIAO PENG

Assignees

中国空气动力研究与发展中心高速空气动力研究所

Dates

Publication Date: 20260512
Application Date: 20260415

Claims (10)

1. The grid division method for the internal and external flow field structures of the aircraft based on the non-matching interface is characterized by comprising the following steps of: The appearance of the aircraft is decomposed into two topological subfields of an external flow field, an air inlet channel and an internal flow field of a tail nozzle, and all subfields are connected through a pair of completely overlapped interfaces; the internal flow field of the air inlet channel and the external flow field of the tail pipe adopts O-shaped topological structure grids, the external flow field adopts C-shaped topological structure grids, and nodes of the O-shaped topological structure grids and the C-shaped topological structure grids can mutually slide on interfaces.
2. The method for meshing the internal and external flow field structures of the aircraft according to claim 1, wherein the O-shaped topological structured meshing corresponding to the flow field in the air inlet and the tail pipe is designed and partitioned according to the following structure, and the method comprises the following steps: The inlet section of the air inlet is taken as a source surface, firstly, the geometric construction line of the air inlet and the spray pipe along the journey is obtained, then, an internal O-shaped block topological structure is arranged on the section with the curvature larger than a preset value, and finally, the O-shaped grid block is generated by adopting polar coordinate transformation along the flow direction.
3. The method for meshing the internal and external flow field structures of the aircraft according to claim 2, wherein in the O-shaped topological structured grid, a single O-shaped grid is used for a round/elliptic section, and for a rectangular section, an O-H combined topology is adopted, namely H-grid transition blocks are added at four corners, so that grid corner points have no singular lines.
4. The method for meshing an internal and external flow field structure of an aircraft according to claim 2, wherein each mesh node of the O-shaped topological structured mesh adopts an exponential growth distribution in a normal direction of a mesh wall surface.
5. The method for meshing an inner flow field structure and an outer flow field structure of an aircraft according to claim 1, wherein the C-shaped topological structure meshing corresponding to the outflow field is designed and divided according to the following structure, and the outer flow field is divided into an accessory surface layer area, a wake area and a far field area; the surface layer area generates C-shaped body-attached grids around the surface of the aircraft, the surface of the aircraft is divided into a plurality of regular quadrilateral blocks in the three-dimensional direction, the regular quadrilateral blocks are used for generating structural grids, and all grid nodes adopt exponential growth distribution in the normal direction of the grid wall surface.
6. A method of meshing an aircraft internal and external flow field structure as set forth in claim 5 wherein said wake area employs a square structured mesh surface to create a three-dimensional volumetric mesh.
7. The method of meshing an internal and external flow field structure of an aircraft according to claim 6, wherein the size of the wake area extends backwards from the tail edge of the aircraft body by a length equal to or more than 20 times, and captures the flow structure generated by the tail jet.
8. The method of meshing an internal and external flow field structure of an aircraft according to claim 5, wherein the far field region employs a square structured mesh surface to generate a three-dimensional volumetric mesh.
9. The method for meshing an internal and external flow field structure of an aircraft according to claim 8, wherein the far field region corresponds to a rectangle with a size of 100 times of a characteristic length with a radius centered on the aircraft body, and the mesh is geometrically grown at a magnification of 1.3.
10. The method for meshing the internal and external flow field structures of the aircraft according to claim 1, wherein two groups of construction lines with completely consistent space positions and geometric lengths are adopted for the butt joint area of the O-shaped topological structure grid and the C-shaped topological structure grid, and an interface adapting to the O-shaped topological structure grid of the internal flow field and an interface adapting to the C-shaped topological structure grid are respectively constructed.

Description

Aircraft internal and external flow field structure grid division method based on non-matching interface Technical Field The application belongs to the field of aerospace and hydrodynamics, and particularly relates to a grid division method for an aircraft internal and external flow field structure based on a non-matching interface. Background With the development of computer technology, computational fluid dynamics methods are widely used in the relevant fields of aerospace and aerodynamics. The method can obtain the global flow field structure of the aircraft, which is important to the pneumatic performance analysis and the optimal design of the aircraft. The principle of the method is that the external continuous flow field of the aircraft is discretized into grids, and then the Navier-Stokes equation is subjected to numerical discretization and solving, so that an approximate solution of the flow field is obtained. Therefore, the adoption of the method inevitably bypasses the grid division of the flow field. The most common current methods are unstructured grids and structured meshing. The non-structural grid is suitable for complex curved surfaces, low in generation difficulty and strong in self-adaptive capability, but low in calculation efficiency, poor in boundary processing capability and high in grid quantity required for flow field filling, the structural grid is high in calculation efficiency, high in grid quantity, low in grid quantity and high in precision, but poor in adaptability in terms of adapting to complex geometric shapes, more in manual intervention and large in requirement for blocking, and the problem of high grid generation difficulty is caused. Currently, in the research of carrying out inner-outer flow coupling on an inner-outer flow integrated aircraft, an unstructured grid is mostly adopted to divide a flow field, and for a complex geometric shape, the grid quantity can be rapidly increased, so that the calculation efficiency is low. When the non-structural grid is adopted, the boundary layer grid is generally arranged as a prismatic layer, but the boundary layer grid is generally provided with the shapes such as large curvature and corners at the joint position of the air inlet channel and the airframe, and is easy to fail when the prismatic layer grid is generated at the joint position. When the structural grid is adopted to divide the internal flow field and the external flow field, the shapes of the air inlet channel and the spray pipe are generally cylindrical, and in order to ensure that boundary layer grids are arranged on the upper wall surface and the lower wall surface, the shapes are generally O-shaped grids. The division of the outer flow field area of the aircraft is generally C-shaped grids, and the grid growth directions of the two areas are mutually perpendicular, so that the inner flow field grid and the outer flow field grid are difficult to use the same topological structure, and the inner flow field and the outer flow field cannot be directly connected. Disclosure of Invention The application aims to overcome the problems in the prior art, discloses a grid dividing method for an inner and outer flow field structure of an aircraft based on a non-matching interface, and aims to solve the problems that in the current complex aircraft appearance inner and outer flow coupling numerical simulation, the non-structural grid has poor adaptability in a boundary layer area near a wall surface, large calculation amount and difficult maintenance of full-field conservation and high precision of a mixed grid. The aim of the application is achieved by the following technical scheme: An aircraft internal and external flow field structure meshing method based on a non-matching interface, the aircraft internal and external flow field structure meshing method comprises the following steps: The appearance of the aircraft is decomposed into two topological subfields of an external flow field, an air inlet channel and an internal flow field of a tail nozzle, and all subfields are connected through a pair of completely overlapped interfaces; The internal flow field of the air inlet channel and the external flow field of the tail pipe adopts O-shaped topological structure grids, the external flow field adopts C-shaped topological structure grids, and nodes of the O-shaped topological structure grids and the C-shaped topological structure grids can mutually slide on interfaces. Namely, due to different topological structures, nodes of the O-type topological structure grid and the C-type topological structure grid do not need to be in one-to-one correspondence on the interface, random slippage is allowed, and grid quality degradation caused by traditional node matching is thoroughly eliminated. According to a preferred embodiment, the O-shaped topological structure grid corresponding to the flow field in the air inlet and the tail pipe is designed and divided according to the followin