Numerical study of wedge supported oblique shock wave-oblique detonation wave transitions

C. A. R. Pimentel, J. L. F. Azevedo, L.F. Figueira da Silva, B. Deshaies
2002 Journal of the Brazilian Society of Mechanical Sciences  
The results of a numerical study of premixed Hydrogen-air flows ignition by an oblique shock wave (OSW) stabilized by a wedge are presented, in situations when initial and boundary conditions are such that transition between the initial OSW and an oblique detonation wave (ODW) is observed. More precisely, the objectives of the paper are: (i) to identify the different possible structures of the transition region that exist between the initial OSW and the resulting ODW and (ii) to evidence the
more » ... to evidence the effect on the ODW of an abrupt decrease of the wedge angle in such a way that the final part of the wedge surface becomes parallel to the initial flow. For such a geometrical configuration and for the initial and boundary conditions considered, the overdriven detonation supported by the initial wedge angle is found to relax towards a Chapman-Jouguet detonation in the region where the wedge surface is parallel to the initial flow. Computations are performed using an adaptive, unstructured grid, finite volume computer code previously developed for the sake of the computations of high speed, compressible flows of reactive gas mixtures. Physicochemical properties are functions of the local mixture composition, temperature and pressure, and they are computed using the CHEMKIN-II subroutines. Figure 2. Successive adapted meshes and corresponding pressure fields. Freestream parameters: M 0 = 7, p 0 = 0.266 atm, T 0 = 300 K and δ δ = 35 deg. Number of nodes and triangles (a): (6802, 13282), (b): (9566, 18777), (c): (15979, 31558) and (d): (40201, 79959). J. of the Braz. Soc. Mechanical Sciences Figure 3. Mach number and OH mass fraction fields for successive adapted meshes. Freestream parameters: M 0 = 7, p 0 = 0.266atm, T 0 = 300K and δ δ = 35 deg. Number of nodes and triangles (a): (6802, 13282), (b): (9566, 18777), (c): (15979, 31558) and (d): (40201, 79959). J. of the Braz. Soc. Mechanical Sciences
doi:10.1590/s0100-73862002000300002 fatcat:t4rjy5mivvg4vgf6us7m4klt4y