A parallel hybrid overset grid assembly method and its application

Abstract

The overset grid method can effectively solve the complex flow problem of large-scale relative motion, but it is difficult to guarantee efficiency and accuracy of the overset grids with over 10 million scale and dozens of components. Based on a hybrid overset grid system that supports unstructured, Cartesian, and polyhedral meshes, an automated and MPI process-level parallel overset grid assembly method is developed in this paper. Combining rigid body motion and Unsteady Reynolds-Averaged Navier-Stokes (URANS) method, the method is suitable for simulating large-scale relative motion problems. The assembly procedure of overset grid includes four steps: hole-cutting, overlap-optimization, donor-searching, and interpolation. The process of hole-cutting combines the local hole mapping method and the direct cut method to quickly predict the overlapping relationship between different sub-grids, then realizes accurate hole-cutting; In the process of overlap-optimization, the wall/hole surface distance method is innovatively used to reduce the grid overlapping area, avoiding a large number of donor-searching operations in the traditional wall distance method; The donor-searching process uses the inverse mapping method and stencil walking method to quickly determine the donor, even across the boundaries such as partition boundaries and physical boundaries. This article uses WPFS store separation case and UH60 rotor hover case to verify the reliability and parallel performance of the developed overset grid assembly method. The results show that the assembly method is suitable for dynamic simulation of complex flow fields, and the parallel performance of overset grid assembly can still meet engineering requirements under extreme load imbalance conditions.

Keywords

overset grid parallel partition parallel hole-cutting parallel overlap-optimization parallel donor-searching

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References

Zhang

Shan

Shi

, et al. Efficient ASM/CFD/CSD coupling method for helicopter numerical virtual fight simulation. Aero Sci Technol 2026; 168: 111206. https://doi.org/10.1016/j.ast.2025.111206

Tian

Chen

. A numerical method for multi-body separation with collisions. Aero Sci Technol 2021; 109: 106426. https://doi.org/10.1016/j.ast.2020.106426

Chang

Wang

, et al. A parallel implicit hole-cutting method based on background mesh for unstructured Chimera grid. Computers and Fluids 2020; 198: 104403. https://doi.org/10.1016/j.compfluid.2019.104403

Roget

Sitaraman

. Robust and efficient overset grid assembly for partitioned unstructured meshes. J Comput Phys 2014; 260: 1–24. https://doi.org/10.1016/j.jcp.2013.12.021

Meakin

. Object X-Rays for cutting holes in composite overset structured grids. In: 15th AIAA Computational Fluid Dynamics Conference, 11 June 2001 - 14 June 2001, 2001. https://doi.org/10.2514/6.2001-2537

Fan

Yan

Zhang

. Improvement of hole-surface optimization technique in overset grids and its application. ACTA Aeronauticaet Astronautica Sinica 2010; 31: 1127–1133, in Chinese. https://hkxb.buaa.edu.cn/EN/Y2010/V31/I6/1127

Bonet

Peraire

. An alternating digital tree (ADT) algorithm for 3D geometric searching and intersection problems. Int J Numer Methods Eng 1991; 31: 1–17. https://doi.org/10.1002/nme.1620310102

Wang

Parthasarathy

. A fully automated Chimera methodology for multiple moving body problems. Int J Numer Methods Fluid 2000; 33: 919–938. https://doi.org/10.1002/1097-0363(20000815)33:7<919::AID-FLD944>3.0.CO;2-G

Wang

. A multiple instance solver framework based on dynamic overset grid method for flow field simulation of array configuration with moving components. J Comput Phys 2022; 448: 110741. https://doi.org/10.1016/j.jcp.2021.110741

10.

Lohner

. Robust, vectorized search algorithms for interpolation on unstructured grids. J Comput Phys 1995; 118(2): 380–387. https://doi.org/10.1006/jcph.1995.1107

11.

Zhang

Fan

Yuan

, et al. Structure overset grid method and its applications to simulation of multi-body separation. Sci China Phys Mech Astron 2015; 58(9): 594702. https://doi.org/10.1007/s11433-015-5689-0

12.

Nakahashi

Togashi

Sharov

. An intergrid-boundary definition method for overset unstructured grid approach. AIAA Journal. AIAA-99-3304 1999. https://doi.org/10.2514/6.1999-3304

13.

Abbruzzese

Gómez

Cordero-Gracia

. Unstructured 2D grid generation using overset-mesh cutting and single-mesh reconstruction. Aero Sci Technol 2018; 78: 637–647. https://doi.org/10.1016/j.ast.2018.05.004

14.

Chang

Zhang

. Parallel implicit hole-cutting method for unstructured overset grid. ACTA Aeronauticaet Astronautica Sinica 2018; 39(6): 121780. https://doi.org/10.7527/S1000-6893.2017.21780

15.

Xuan

Han

. Enhancement of implicit assembly strategy in overlapping grids. J Beijing Univ Aeronaut Astronaut 2020; 46(2): 350–358. https://doi.org/10.13700/j.bh.1001-5965.2019.0260

16.

Noack

Boger

Kunz

, et al. Suggar++: an improved general overset grid assembly capability. AIAA J 2009, AIAA-2009-3992. https://doi.org/10.2514/6.2009-3992

17.

Noack

Wyman

McGowan

, et al. Dual-Grid interpolation for cell-centered overset grid systems. AIAA Journal, AIAA 2020: 1407. https://doi.org/10.2514/6.2020-1407

18.

Sitaraman

Floros

Wissink

, et al. Parallel domain connectivity algorithm for unsteady flow computations using overlapping and adaptive grids. J Comput Phys 2010; 229(12): 4703–4723. https://doi.org/10.1016/j.jcp.2010.03.008

19.

Sitaraman

Jude

Roget

, et al. Algorithmic improvements and capability enhancements to PUNDIT. AIAA J 2022: 1175. https://doi.org/10.2514/6.2022-1175

20.

Chaderjian

. Navier-stokes simulation of UH-60A Rotor/Wake interaction using adaptive mesh refinement. In: AHS International 73rd Annual Forum & Technology Display. Fort Worth, TX, May 9-11, 2017, 2017. https://ntrs.nasa.gov/citations/20170009808

21.

Spalart

Jou

W-H

Strelets

, et al. Comments on the feasibility of LES for wing and on a hybrid RANS/LES approach. In: Advances in DNS/LES: Direct numerical simulation and large eddy simulation, 1997, pp. 137–148.

22.

Chaderjian

. Advances in rotor performance and turbulent wake simulation using DES and adaptive mesh refinement. In: 7th International Conference on Computational Fluid Dynamics (ICCFD7), Big Island, Hawaii, July 9-13, 2012, 2012. Paper No. ICCFD7-3506.