Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Numerical and Experimental Study of Some Blast Wave Phenomena

Numerische und experimentelle Untersuchung einiger Blastwellen-Phänomene
: Toro, E.F.; Heilig, W.; Jochims, M.

19th International Symposium on Shock Tubes and Waves '93. Proceedings
Marseille, 1993
International Symposium on Shock Tubes and Waves <19, 1993, Marseille>
Fraunhofer EMI ()
Mach reflection; Mach-Reflexion; piezoelectric gages; Piezoelektrische Druckgeber; regular reflection; Regular-Reflexion; Schatten-Schlieren-Bild; shadow-schlieren pictures; Visualisierung; visualisation

Visualization and measuring techniques for blast wave propagation in gases can be useful in assessing new numerical schemes, so that these can then be used with certain confidence in the study of fluid dynamic phenomena in realistic situations. In the present paper we deal with two blast wave processes in air: the attenuating effect of an expansion chamber with respect to the incoming blast wave and the reflection of a spherical explosion wave from a plane wall. Extensive comparisons between numerical and experimental results are carried out. Piezoelectric gages mounted at appropriate positions of the models enable to record pressure-time histories from which pressure data can be evaluated. The processes are studied in laboratory dimensions, however, extrapolation to large dimensions is valid due to the scaling laws. Shadow-schlieren pictures of these strongly time-dependent events are presented. We apply the Weighted Average Flux (WAF) method together with a Riemann-solver adaptation procedure that ensures both efficiency and robustness. Here the method is extended to solve the three-dimensional time-dependent Euler equations. The scheme is applied to the two processes referred to above and its performance assessed via experimental data. For the first process it reveals a second vortex shock not visible in the experiment. An attempt to explain it is made. The corresponding comparison for the spherical explosion (second process) is performed. Here the emphases of regular and Mach reflection are treated. The overall agreement with experimental data is satisfactory.