In any supersonic intake, the flow decelerates from supersonic to subsonic speed through a constant or divergent channel "isolator" by a series of bifurcated compression shock waves referred to as a shock train. It is important to understand the characteristics of the shock train which occur inside the isolator to improve the performance of scramjet engines. In the present work, numerical simulations were carried out to investigate the characteristics of the shock train occurring in the divergent channels using coupled implicit Reynolds Averaged Navier-Stokes (RANS) equations along with the two-equation k-w SST turbulence model. Results show that the downstream pressure variation causes the shock train length to decrease and the shock structure phenomenon varies from Mach reflection to Regular reflection. The variation of the inlet Mach number has less influence on the shock train length and the location of the shock train is determined by the area ratio. In comparison with the constant area duct, the shock train structure phenomena varies from Mach reflection to regular reflection in the divergent channel. Also, the increase in divergent angle raises the total pressure loss.

A laser shock cleaning (LSC) technique as a new dry cleaning methodology has been applied to remove micro and nano-scale inorganic particulate contaminants. Shock wave is generated in the air just above the wafer surface by focusing intensive laser beam. The velocity of shock wave can be controlled to 10,000 mlsec. The sub-micron sized silica and alumina particles are attempted to remove from bare silicon wafer surfaces. More than 95% of removal efficiency of the both particles are carriend out by the laser-induced airborne shock waves. In the final, a removal of nano-scale slurry particles from real patterned wafers are successfully demonstrated by LSC after chemical-mechanical polishing (CMP) process.