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In this study, the CW laser is used as a local heat source to simulate the extreme thermal environment generated by shock wave interference at discontinuities in spacecraft. The ablation behavior of the thermal protection material (C/SiC) is investigated under the combined impact of high-temperature airflow and the local extreme heat source. A novel multi-field coupling numerical computation software was presented to examine this strong coupling process of fluid-solid-thermal-ablation. The program was modified using the ALE + umeshmotion ablation calculation method in the ABAQUS software to mimic the process of the material's ablative boundary retreating under the action of the CW laser until the target was perforated. ANSYS Fluent software was used to do the numerical analysis of the high-speed airflow. The results of wind tunnel experiments and numerical simulations indicate that, compared to the effect of local heat sources in static air, irregular ablation pits are formed on the material surface under the action of local heat sources in high-temperature flow fields, resulting in higher ablation rates due to mechanical denudation effects. Analysis of the localization characteristics of the flow field near the ablation pit reveals that the shock wave generated downstream of the ablation pit leads to an increase in gas temperature, pressure, and density. When the ablation amount reaches a certain threshold, the gas in the ablation pit forms vortices, leading to an increase in local heat flow and pressure. [ABSTRACT FROM AUTHOR]

A numerical method is presented to study the air-flow pattern and particle trajectory in the head–disk interface (HDI) in this paper. It first solves the generalized steady-state Reynolds equation with slip boundary conditions to get the slider attitude. Then, it solves the reduced Navier–Stokes equation to get the air flow velocity distribution in the HDI. The motion equations of particles are solved to obtain the particle trajectory in the HDI by using the fourth-order Runge–Kutta method. Air flow characteristics and particle behaviors are investigated to illustrate the relationship between the air flow and particle trajectory. The effect of the particle release height is also studied. The simulation results show that particle trajectories basically overlap air flow streamlines in the horizontal plane. The particle moves a longer horizontal distance at a lower particle release height. The difference between the horizontal velocity of the particle and the air flow indicates that the Saffman force points to the disk in the transition region close to the leading edges of leading pads. Moreover, the peak values of the air flow vertical velocity in the previously mention location increase with the reduction of the particle release height. And the air flow vertical velocity along the particle trajectory is almost two times larger than that of the particle at the leading edges of leading pads. The results also show that the drag force of the air flow mainly drives particles up toward the air bearing surface at the leading edges of leading pads, but not the Saffman force. [ABSTRACT FROM PUBLISHER]