ShockFluidX: A Novel OpenFOAM-Based Modular Solver for High-Speed Flows

Engineering Mechanical Engineering Aerospace Engineering
Computational Fluid Dynamics High-Speed Flows OpenFOAM Modular Solver Adaptive Mesh Refinement

Academic Background

Hypersonic technology is a critical research direction in the aerospace field, with applications spanning national defense, space launch, and ultra-high-speed commercial aviation. With the rapid development of Computational Fluid Dynamics (CFD) technology, high-fidelity CFD simulations play an increasingly important role in the design of hypersonic vehicles. However, despite the widespread use of open-source CFD frameworks like OpenFOAM, existing density-based solvers face numerous limitations in meeting the complex demands of modern hypersonic vehicle design. In particular, the high licensing costs and closed-source nature of commercial software restrict their widespread adoption, while existing open-source tools still fall short in terms of algorithm maturity, functional completeness, and validation.

To address these issues, a team led by Shang Wang and Xiaobing Zhang from the School of Energy and Power Engineering at Nanjing University of Science and Technology developed a novel modular compressible flow solver based on OpenFOAM v12—ShockFluidX. Building upon the existing ShockFluid framework, this solver introduces several key innovations aimed at improving computational efficiency and accuracy, particularly in handling complex hypersonic flow problems. The research was published on April 18, 2025, in the journal Physics of Fluids, under the title “ShockFluidX: A Novel OpenFOAM-Based Modular Solver for High-Speed Flows.”

Research Process and Innovations

1. Solver Architecture and Design

The core design of ShockFluidX is based on the modular architecture of OpenFOAM v12. By introducing the PIMPLE algorithm, it achieves stability comparable to Runge-Kutta temporal schemes while maintaining computational efficiency. The main functional modules of the solver include:

  • FluxSchemes Module: Implements various convective flux computation methods, such as Kurganov, Tadmor, Roe, HLL family, and AUSM family.
  • FluxLimiters Module: Introduces multiple high-resolution Total Variation Diminishing (TVD) flux limiters, including SGVA, SGVL, SGPRK, and SSFL.
  • MultiDimAMR Module: Supports multi-dimensional Adaptive Mesh Refinement (AMR), including dynamic load balancing for 1D, 2D, 2.5D, and 3D meshes.
  • FVModels Module: Handles complex physical processes and their interactions with the main solver, such as Lagrangian particles, radiation, and surface films.
  • FVConstraints Module: Manages numerical constraints and solution limitations to ensure solution stability and physical bounds.

2. Numerical Methods and Extensions

ShockFluidX extends its numerical methods to enhance its capability in handling hypersonic flows:

  • Extension of Convective Flux Schemes: Through the Run-Time Selection (RTS) mechanism, users can dynamically choose different convective flux computation methods, such as Kurganov, Tadmor, Roe, HLLC, and AUSM family.
  • Implementation of High-Resolution Flux Limiters: Introduces multiple high-resolution flux limiters, such as SGVA, SGVL, SGPRK, and SSFL, as well as the Round family schemes, significantly improving numerical accuracy and stability.
  • Development of Multi-Dimensional AMR: By modifying and integrating community contributions for 2D and axisymmetric cases, it achieves multi-dimensional AMR for 1D, 2D, 2.5D, and 3D cases, supporting dynamic load balancing (DLB).

3. Verification and Validation Studies

To validate the performance of ShockFluidX, the research team conducted systematic verification and validation studies, ranging from simple one-dimensional problems to complex two-dimensional flow problems. Key validation cases include:

  • One-Dimensional Shock Tube Problem: Through comparisons of numerical solutions with exact solutions for the Sod and Lax problems, the effectiveness of the PIMPLE algorithm in improving computational stability and accuracy was verified.
  • Shu-Osher Problem: By simulating the propagation of a Mach 3 shock through a sinusoidal density field, the superior performance of high-resolution flux limiters in capturing shock-turbulence interactions was validated.
  • Two-Dimensional Riemann Problem: By simulating complex wave interactions, the capability of ShockFluidX in handling multi-dimensional flow problems was verified.
  • Double Mach Reflection Problem: By comparing results from different solvers and mesh strategies, the effectiveness of multi-dimensional AMR and dynamic load balancing modules in improving computational efficiency and accuracy was validated.

Key Results and Conclusions

1. One-Dimensional Shock Tube Problem

In the numerical simulations of the Sod and Lax problems, ShockFluidX demonstrated superior computational stability and accuracy compared to RhocentralFoam and BlastFoam. Particularly, with the PIMPLE algorithm, ShockFluidX significantly reduced numerical oscillations, ensuring solution stability and boundedness.

2. Shu-Osher Problem

With the support of high-resolution flux limiters, ShockFluidX outperformed the traditional van Leer limiter in capturing shock-turbulence interactions. Specifically, with the use of SGVA, SGVL, SGPRK, and SSFL limiters, ShockFluidX significantly reduced numerical dissipation and improved shock-capturing capabilities.

3. Two-Dimensional Riemann Problem

In the numerical simulation of the two-dimensional Riemann problem, ShockFluidX demonstrated superior computational accuracy and stability compared to traditional limiters. Particularly, with the use of the Round family limiters, ShockFluidX was able to better capture Kelvin-Helmholtz (K-H) instability structures along slip lines.

4. Double Mach Reflection Problem

With the support of multi-dimensional AMR and dynamic load balancing modules, ShockFluidX significantly improved computational efficiency in the double Mach reflection problem. Compared to BlastFoam and RhocentralFoam, ShockFluidX achieved the same computational accuracy while reducing computation time by 15% to 260%.

Research Significance and Value

The development of ShockFluidX marks a significant advancement in open-source CFD tools for hypersonic flow simulations. Its modular design and high-resolution numerical methods not only improve computational efficiency and accuracy but also provide a powerful numerical simulation tool for future multi-physics coupling applications. The successful validation of this solver opens new possibilities for high-fidelity CFD simulations in aerospace engineering, particularly in handling complex hypersonic flow problems.

Research Highlights

  • Modular Design: The modular architecture of ShockFluidX facilitates the seamless integration of new functionalities while maintaining code maintainability and computational efficiency.
  • High-Resolution Numerical Methods: By introducing multiple high-resolution flux limiters and the Round family schemes, ShockFluidX significantly improves numerical accuracy and stability.
  • Multi-Dimensional AMR and Dynamic Load Balancing: ShockFluidX supports 1D, 2D, 2.5D, and 3D multi-dimensional AMR and implements dynamic load balancing, significantly enhancing computational efficiency and resource utilization.

Future Outlook

Future research will focus on the following areas: - Implementation of Additional Convective Flux Schemes: Such as HLLC-LM, to support all-Mach number computations. - Extension of Multi-Dimensional AMR Capabilities: Supporting anisotropic refinement for arbitrary polyhedral meshes. - Validation of Multi-Component and Lagrangian Modules: Further improving the solver’s applicability in complex engineering applications.

Through continuous optimization and extension, ShockFluidX is expected to become a benchmark tool in hypersonic flow simulations, providing more accurate and efficient numerical simulation solutions for aerospace engineering.