| Abstract: | In addition to physical experiments, numerical experiments are widely used for the investigation of complex gasdynamic and magnetogasdynamic flows with various internal surfaces of discontinuity and are found to yield the most complete quantitative results. In the investigation of two-or three-dimensional flows by numerical methods, however, the interpretation of the results poses more than a trivial problem, because the internal discontinuity surfaces are diffuse in the majority of situations. Some surfaces vanish altogether (such as the contact surfaces in application of the  particle-in-cell method), while others, such as second shocks, can be identified by investigation of the flow parameters in the suspicious region. The kind of experience needed for the latter is most readily acquired in the calculation and analysis of complex flows with known qualitative singularities. A suitable candidate for this standard flow is the flow associated with shock diffraction, the qualitative singularities of which have been investigated in sharp detail in experimental work [1, 2]. The particle-in-cell (PIC) method [3, 4] is used in the present work to investigate the flow associated with diffraction of a shock wave by a 90 corner. The scheme of the described flow is borrowed from Skews [1] and has been used in our earlier work [5], in which we showed that PIC analysis yields a correct expression for the diffracted shock and exhibits the presence of flow separation in the resulting second shock.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 125–129, September–October, 1976. |
