The free-vortex aerodynamic windows (abbr. FADW) can take the place of the conventional solid windows for high energy lasers to solve the problems caused by the intrinsic fractional absorption of the laser energy. Usually the procedure in designing FADW includes two central processes. The first is to design the asymmetric supersonic laval nozzle using the method of characteristics and the method of simple wave under the ideal conditions, and the second is to design the diffuser. The method of designing the diffuser of FADW is based on the experimental method mostly, but the diffuser's properties influences the performance ofthe overall FADW system deadly, so an experimental prototype of FADW whose structure and layout is adjustable has been designed and manufactured to optimize the design of the diffuser for FADW system. This paper reports the design methods of the FADW system and discusses the experimental results. The results show that this prototype of the FADW has good running properties, and FADW whose structure and layout is adjustable can be used to optimize the FADW design perfectly.
The concept of the free-vortex aerodynamic windows (FADW) is one of the best effective methods taking the place of the conventional beam output crystal windows of high power laser. An experimental model of the supersonic free-vortex aerodynamic window has been designed and made in our latest study. This paper studies the aero-optical phenomena of the FADWs supersonic jet to realize the laser optical quality degradation caused by the free- vortex jet, and to find out the relation of output laser beam quality through the FADW to the structure of the FADWs shearing interferometry. At last the structure of FADWs jet has been studied by means of shearography.