Light emission during shock wave focusing in air and argon

Författare: Eliasson, V., Tillmark, N.T., Szeri, A. J., Apazidis, N.
Dokumenttyp: Artikel
Tillstånd: Accepterad
Tidskrift: Physics of fluids A
År: 2007


The light emission from a converging shock wave was investigated experimentally. Results show that the shape of the shock wave close to the center of convergence has a large influence on the amount of emitted light. It was found that a symmetrical polygonal shock front produced more light than an asymmetrical shape. The light emission appears as the shock wave collapses. The full width at half maximum of the light pulse is about 200 ns for all geometrical shapes. It was also found that argon as a test gas produces more light than air. Numerical simulations showed good agreement with experimental results regarding the shape of the shock and the flow field behind the shock. The temperature field from the numerical simulations was investigated and shows that the triple points behind the shock front are hot spots that increase the temperature at the center as they arrive there.