Research interest has been growing in recent years in supersonic transport, particularly supersonic propulsion systems. A key component of a commonly studied propulsion system, ramjets, is the air intake. For supersonic propulsion systems a major factor in the overall efficiency is the intake pressure recovery. This refers to the ratio of the average total pressure after the intake to that of the freestream. One phenomenon that can have a large effect on this performance index is flow separation at the inlet. The aim of this work is to examine how pulsed laser energy deposition can be used to improve pressure recovery performance by reducing flow separation at the inlet. This research examines the effects of pulsed laser energy deposition upstream of an intake with an axisymmetric centrebody in a Mach 1.92 indraft wind tunnel. Laser frequency was varied between 1 and 60 kHz with an energy per pulse of 5.6 mJ. Schlieren photography was used to examine the fundamental fluid dynamics while total and static pressure downstream of the intake diffuser were measured to examine the resulting effect on the performance. Schlieren imaging shows that the interaction between the laser generated thermal bubble and the leading edge shock produced by the centrebody results in a significant reduction in separation along the intake cone. Analysis of the schlieren results and the pressure results in tandem illustrate that the average separation location along the length of the centrebody directly correlates to the pressure recovery observed in the intake. At the optimal laser frequency, found for this Mach number to be 10 kHz, the pressure recovery is found to increase by up to 4.7%. When the laser power added to the system is considered, this results in an overall increase in propulsive power of 2.47%.

近年来，对超音速运输，特别是超音速推进系统的研究兴趣已经增长。进气口是通常研究的推进系统冲压发动机的关键组成部分。对于超音速推进系统，总效率的主要因素是进气压力的恢复。这是指进气后的平均总压力与自由流的平均总压力之比。可能对该性能指标产生重大影响的一种现象是入口处的流量分离。这项工作的目的是研究如何通过减少入口处的流分离来使用脉冲激光能量沉积来改善压力恢复性能。这项研究检查了马赫1.92吸风隧道中轴对称中心体进气口上游脉冲激光能量沉积的影响。激光频率在1至60 kHz之间变化，每个脉冲能量为5.6 mJ。使用Schlieren摄影技术检查基本流体动力学，同时测量进气扩散器下游的总压力和静压力以检查对性能的影响。Schlieren成像显示，激光产生的热气泡与中心体产生的前缘冲击之间的相互作用会导致沿进气锥的分离明显减小。对schlieren结果和压力结果的分析表明，沿着中心体长度的平均分离位置与进气口中观察到的压力恢复直接相关。在此马赫数为10 kHz的最佳激光频率下，发现压力恢复提高了4.7％。