Heat Transfer and Mode Transition for Laser Ablation Subjected to Supersonic Airflow**Supported by the National Natural Science Foundation of China under Grant Nos 11332011 and 11472276, the Project of the Chinese Academy of Sciences, and the Defense Industrial Technology Development Program.

Abstract

When laser ablation is subjected to supersonic flow, the influence mechanism of airflow on laser ablation behavior is still unclear. A coupled thermal-fluid-structure model is presented to investigate the influence of supersonic airflow on the development of a laser ablation pit. Results show that the aerodynamic convection cooling effect not only reduces the ablation velocity but also changes the symmetry morphology of the ablation pit due to the non-uniform convective heat transfer. Flow mode transition is also observed when the pit becomes deeper, and significant change in flow pattern and heat transfer behavior are found when the open mode is transformed into the closed mode.