Major research outcome
- Ph.D. Candidate Woonghwi Park and Professor Eunji Jun, Velocity-dependent surface corrugation model for gas-surface scattering
- 관리자 |
- 2025-09-29 09:51:36|
- 223
- 2025-09-29 09:51:36|
Gas-surface interaction is a fundamental physical phenomenon that describes the exchange of momentum and energy between gas particles and a solid surface. This interaction changes significantly with the particle's incident energy. In the low-energy "thermal scattering" regime, the surface's thermal vibrations are dominant. In contrast, in the high-energy "structure scattering" regime, particles penetrate deeper, and the interaction is governed by the surface's atomic-scale roughness, or corrugation. Because the underlying physics transitions between these regimes, a unified model that can capture both is essential for accurate predictions across a wide range of operating conditions. However, conventional models like the Maxwell and CLL (Cercignani–Lampis–Lord) models, while effective for thermal scattering, assume a smooth surface and thus fail to describe structure scattering. Conversely, models like the washboard model that incorporate corrugation violate the physical principle of reciprocity. Even recent hybrid approaches fell short by applying a fixed level of surface roughness, failing to reflect the reality that higher-energy particles experience stronger corrugation effects.
The Non-equilibrium Gas & Plasma Laboratory at the Department of Aerospace Engineering, KAIST (Adviser: Prof. Eunji Jun) has developed a novel gas-surface interaction model, the “Corrugated CLL model,” which incorporates the effects of surface corrugation dependent on incident velocity. This model employs a “velocity-dependent corrugation factor”, which accurately reflects the physical reality that high-velocity particles penetrate deeper into the surface, experiencing greater roughness.
Validation against molecular beam scattering experiments shows that the Corrugated CLL model successfully reproduces complex physical behaviors, such as the non-monotonic angular distribution that narrows in the thermal regime and broadens in the structural regime. This model provides a unified and physically consistent framework for describing gas-surface scattering over a wide range of incident energies, and is expected to contribute to precision simulation technologies essential for the future development of hypersonic vehicles and satellites.
This research has been published in the 37th volume, issue 9 of the Physics of Fluids journal in 2025. (IF: 4.1, JCR 분야 상위 5%)
Title: Velocity-dependent surface corrugation in gas-surface scattering
DOI: https://doi.org/10.1063/5.0276122
The Non-equilibrium Gas & Plasma Laboratory at the Department of Aerospace Engineering, KAIST (Adviser: Prof. Eunji Jun) has developed a novel gas-surface interaction model, the “Corrugated CLL model,” which incorporates the effects of surface corrugation dependent on incident velocity. This model employs a “velocity-dependent corrugation factor”, which accurately reflects the physical reality that high-velocity particles penetrate deeper into the surface, experiencing greater roughness.
Validation against molecular beam scattering experiments shows that the Corrugated CLL model successfully reproduces complex physical behaviors, such as the non-monotonic angular distribution that narrows in the thermal regime and broadens in the structural regime. This model provides a unified and physically consistent framework for describing gas-surface scattering over a wide range of incident energies, and is expected to contribute to precision simulation technologies essential for the future development of hypersonic vehicles and satellites.
This research has been published in the 37th volume, issue 9 of the Physics of Fluids journal in 2025. (IF: 4.1, JCR 분야 상위 5%)
Title: Velocity-dependent surface corrugation in gas-surface scattering
DOI: https://doi.org/10.1063/5.0276122
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