Particle-velocity gauge system for nanosecond sampling rate of shock and detonation waves

A high-resolution, particle-velocity gauge system was developed to obtain a hydrodynamic streamline in the flow field associated with shock waves or detonation products. The system is composed of a passive current loop (stirrup probe) embedded in the host material, a magnetic field generator to establish a Lorentz force, and a computer-controlled, analog-to-digital transient recorder to monitor the gauge response. The operation principle is that the motion of one side of a rectangular loop in a magnetic field produces a current proportional to the velocity of that leg. System tests were conducted with 50-mm diam. by 50-mm long cylinders of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) explosive and explosive-driven polytetrafluoroethylene (PTFE). The velocity profiles obtained have a time resolution of a few nanoseconds with an amplitude uncertainty of approximately 2% based on a system error analysis. Detailed descriptions of the gauge system components are included.