Method for acquiring non-local variable information of boundary layer of unstructured grid

An unstructured grid, variable information technology, applied in the field of boundary layer transition prediction in fluid mechanics, can solve problems such as limiting transition mode, application of transition criterion method, and difficulty in improving prediction accuracy.

Active Publication Date: 2021-05-18
BEIJING INSTITUTE OF TECHNOLOGYGY +1
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Problems solved by technology

However, in the construction process of these two methods, some boundary layer non-local variable information will be used, such as: cross-flow velocity w in the boundary layer, maximum cross-flow velocity w max , boundary layer momentum thickness θ, momentum thickness Reynolds number Re θ , Velocity u at the outer edge of the boundary layer e , Mach number Ma at the outer edge of the boundary layer e and the temperature T of the outer edge of the boundary layer e , etc., these parameters are difficult to obtain in modern computational fluid dynamics (CFD) methods based on large-scale parallel and unstructured grids, which greatly limits the transition mode and transition criterion method in complex shape boundary layer transition prediction It is difficult to improve the prediction accuracy in the application of

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  • Method for acquiring non-local variable information of boundary layer of unstructured grid
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  • Method for acquiring non-local variable information of boundary layer of unstructured grid

Examples

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Embodiment 1

[0080] This example describes a specific embodiment of the application of the method of the present invention to the T3A plate.

[0081] figure 1 It is a flowchart of the method of the present invention. figure 2 It is a schematic diagram of grid preprocessing by the method of the present invention. image 3 It is a schematic diagram of modifying the outer edge of the boundary layer based on the unstructured grid in the present invention. Based on this, the specific implementation of the present invention in a specific application scenario is described.

[0082] The calculation domain of the T3A plate is a rectangle with length L=1000mm, height H=150mm, and the distance between the entrance and the front edge of the plate is 80mm. The calculation adopts mixed grids, the structured grids inside the boundary layer, the unstructured grids outside the boundary layer, and the grids near the wall and the front edge of the plate are densified. In the boundary layer, there are 11...

Embodiment 2

[0086] This example describes the specific implementation of applying the method of the present invention to the calculation model of the swept cylinder.

[0087] The cylinder radius is 30mm and the sweep angle is 50°. The free flow and wall conditions are: Ma ∞ = 3, Re ∞ =2.83×10 7 / m,T ∞ =121.42K,T w = 300K. The grid height of the first layer of the wall guarantees y + =1, the grid near the shock wave position is denser. The wall is set as a non-slip solid wall edge strip, with periodic edge strips on both sides.

[0088] According to the method for grid preprocessing and obtaining boundary layer information provided by the present invention, the cross flow velocity distribution in the boundary layer of the swept cylinder is obtained. Figure 6 is the azimuth Dimensionless cross-flow velocity w / u obtained in the range e Compared with the literature results of Balakumar et al., it can be seen that the difference The cross-flow velocity profile of the station is bas...

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Abstract

The invention relates to a method for acquiring non-local variable information of a boundary layer of an unstructured grid, and belongs to the technical field of boundary layer transition prediction in fluid mechanics. According to the method, firstly, grids are preprocessed, all calculations for acquiring boundary layer information are completed in the w(i, j) array, and the i representing wall grid units in the w(i, j) array is independent from one another, so that large-scale parallel calculation can be performed, and the method is suitable for a modern CFD calculation method. The nearest wall surface distance is searched by adopting a circulating box method, and the reordering of the grids is completed on the basis, so that the calculation efficiency is relatively high. As the w(i, j) array is basically along the normal direction of the wall surface, and wall surface distance correction, boundary outer edge and boundary layer non-local variable parameter correction are carried out, the obtained result has high precision.

Description

technical field [0001] The invention relates to a method for obtaining boundary layer non-local variable information for an unstructured grid, and belongs to the technical field of boundary layer transition prediction in fluid mechanics. Background technique [0002] For a long time, as a frontier and difficult problem in the field of fluid mechanics, boundary layer transition has received extensive and continuous attention. Although the basic theory and mechanism of boundary layer transition are still under development, its importance in engineering practice has become increasingly prominent. For example, in the field of aerospace engineering, the location and development process of the transition have a significant impact on the lift-drag characteristics, boundary layer separation, and surface aerodynamic heating of the aircraft. Therefore, accurate prediction of the boundary layer transition is very important for aerospace The design of aircraft aerodynamic shape and con...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F30/23G06F30/28
CPCG06F30/23G06F30/28
Inventor 周玲黄明珂郝子辉季路成
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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