Many thanks to Jake Letkemann and Eben Anderson-Ciccone for their successful presentations on the Aviation Forum in Las Vegas!
Comparison of Surface Chemistry Models for the Calculation of Refractive Index Along Hypersonic Vehicle, https://arc.aiaa.org/doi/10.2514/6.2025-3481
Chemical kinetic schemes for ablating surfaces in a hypersonic flow were implemented as a boundary condition using the Park, ACA, and Z-A gas-surface models. The models were tested for the hypersonic flow at the RAM-C-II flight conditions. Good agreement was found between the plasma density in these models and the electron density data measured by RAM-C-II’s microwave reflectometers and electrostatic probe. Implementation of the ablation models showed strong increases in the refractive index near the 0.21-m cross section surface at 100 % in the Z-Amodel, 77 % in the ACA model, and 72 % in the Park model. Farther from the wall, small differences of about 3 % were also observable between models. The concentrations of the primary carbonaceous ablation products, the gradients and shapes of the species distributions were distinct between all three models, providing key characteristics for the model validation in future experiments using optical emission spectroscopy
Analysis of Magnetic Field Effects on Radio Signal Propagation Through Hypersonic Layer Plasma, https://arc.aiaa.org/doi/10.2514/6.2025-3849
This study investigates the propagation of a radio frequency (RF) signal through the hypersonic plasma layer for three cases such as Mach 15.5 flow at 30 km, Mach 12 flow at 20 km, and Mach 12 preheated flow. The main focus of the research is on the influence of the external magnetic field on the characteristics of wave transmission at various signal frequencies. A combined numerical approach including computational fluid dynamics (CFD), geometric optics, and the scattering matrix method (SMM) was used to simulate propagation of the RF signal through the hypersonic plasma layer near a wedge surface. It has been shown that at low signal frequencies the applied magnetic field led to a monotonic increase in signal transmission. In contrast, high-frequency signals exhibit a hybrid resonance phenomenon, where the transmission initially decreases with increasing magnetic field strength before recovering at larger magnetic field values. A distinct phase shift in the reflected wave is used to identify these resonance regions, suggesting potential for a diagnostic method of measuring plasma density in a hypersonic plasma layer.
Team from ALLEMO on the Aviation Forum! The AIAA has a new logo!
(Form left to right: Dr. Miles, Dr. Tropina, Jake Letkemann, Eben Anderson-Ciccone, Lukas Robirds, Amir Rad).
