A Three-Dimensional Two-Temperature Gas-Kinetic Scheme with Generalized Kinetic Boundary Condition for Hypersonic SBLI

TL;DR

This paper introduces a 3D two-temperature gas-kinetic scheme with a generalized boundary condition for hypersonic flows, improving accuracy in predicting shock interactions and thermal loads in non-equilibrium conditions.

Contribution

The work develops a novel 3D 2T-GKS with a generalized kinetic boundary condition and a discontinuity feedback factor, enhancing simulation accuracy for hypersonic SBLI with complex shock and heat transfer features.

Findings

Accurately captures shock structures and flow separation.

Predicts surface heat flux distributions with high fidelity.

Validated against experimental benchmarks.

Abstract

Accurate prediction of aerothermal loads in hypersonic flows is critical yet challenging due to the coupling of Shock-Wave/Boundary-Layer Interactions (SBLI) and thermal non-equilibrium. This work presents the development of a three-dimensional two-temperature Gas-Kinetic Scheme (3D 2T-GKS) on unstructured meshes. The scheme resolves translational-rotational and vibrational energy modes within a unified kinetic framework. A key innovation is the integration of a Generalized Kinetic Boundary Condition (GKBC), which physically decouples the thermal accommodation of vibrational energy from the translational-rotational mode, thereby offering a more accurate model for gas-surface interactions. Additionally, a Discontinuity Feedback Factor (DFF) is employed to capture strong shock waves with reduced numerical dissipation compared to classical limiters. The method is rigorously validated against standard experimental benchmarks, including the sharp double-cone and hollow cylinder-flare configurations. Numerical results demonstrate that the proposed solver, augmented by the GKBC, accurately captures complex wave structures, separation topologies, and surface heat flux distributions. These findings confirm the robustness and fidelity of the 3D 2T-GKS for simulating complex hypersonic non-equilibrium flows.