Numerical Analysis of a Blast Wave Using CFD-CAA Hybrid Method

Abstract

CFD (computational fluid dynamics)-CAA (computational aeroacoustics) coupled methods are developed for the analysis of blast noise. Using CFD methods and CAA methods, a distributed monopole problem is simulated and the results are compared to each other. These results show the difference between CFD methods and CAA methods, and give the need of CFD-CAA coupled methods. The developed CFD-CAA coupled methods are applied to analysis of supersonic shock noise for validation. From the results, the developed methods can be used for not only simple cases but also complicated practical cases. After validation, the developed methods are applied to the problem of real high pressure condition and compared with experimental data. For near field flow analysis, the realistic condition of high pressure is simulated without projectile effect. Using a silencer of simple type, we can reduce maximum pressure of blast noise up to 76%. And the effect of key parameters such as diameter, length of a silencer and number of baffle are investigated. For noise analysis, noise of near field and far field is calculated both with silencer and without silencer. From the noise directivity map, we can know the characteristics of a blast noise and its silencer.