Influence of Laser Energy Deposition Conditions on the Drag of A Sphere in Supersonic Flow

Abstract

In the present study, a two-dimensional axisymmetry unsteady numerical simulation that implements high-frequency laser energy deposition was performed to understand its influence on drag reduction in supersonic flow. The energy deposition was modeled as the increase of the temperature inside the focal region. The drag reduction characteristics were investigated by changing the frequency of the deposition, the distance between the focus of the deposition and the body, and the power of the laser. The results showed that drag could be reduced by 60% when there was a single energy deposition. As the operating frequency increased, up to 70% drag reduction was obtained. When the laser energy was deposed more frequently than 75 kHz, the normalized drag converged regardless of the deposition scenario, which resulted from the multiple interactions between the blast wave and the reflected shock. A similar tendency was found from the results of various focal distances. According to the results of this study on the effect of the deposition energy, it is expected to achieve the same effect as with low energy by increasing the frequency of the deposition.