The primary objective of the present work is to investigate the mixing phenomenon in supersonic condition for application in scramjet combustor. it is well-known that at higher supersonic speed the residence time of fuel and air is extremely short which poses a challenge to the self-sustained combustion. efficient combustion is vital to the overall efficiency of the engine cycle. the literature review suggests the existence of an enormous volume of research for the supersonic injection strategy, however, to name few; the most studied configurations is normal injection techniques. however, in the present study, the parallel injection technique is investigated due to its superiority over the normal injection case. the parallel injector assures low total pressure loss and contributes towards to the overall thrust of the engine. the available literature on supersonic mixing layer suggests that the convective mach number (mc) is the most critical parameter that has the direct effect on the mixing. however, the literature also indicates that at the higher convective mach number, i.e., at supersonic speeds, the mixing layer growth is inhibited. this is primarily due to the lack of coherence and the presence of three-dimensionality in the flow field. since all the study reported in the literature is conducted mostly with the splitter plate arrangement, the initial part of the study focuses on studying a real strut based injector at two mc. the investigation is carried out in such a fashion that the effect of convective mach number, three-dimensionality and lip thickness are included in the study. first set of simulation has been performed with the planar hydrogen jet for two strut geometry namely tapered and straight to demonstrate the role of mc. two convective mach numbers vary in such a way that the effect of compressibility on turbulence is negligible for one case (mc=0.37) and significant for the other (mc=1.4). the mc=0.37 being very close to the incompressible regime and mc =1.4 flow being at the high supersonic regime will experience very different level of compressibility. the study reveals that the mixing layer growth gets enhanced for the higher convective mach number as opposed to the existing knowledge in the literature which is a remarkable finding. this leads to the question that which parameters affect the near-field mixing if convective mach number has the least role to play. the study points out that irrespective of the mc, higher velocity gradient in the vicinity of the jet exit plays the significant role. the higher velocity gradient assures enhanced turbulence which is desirable for the diffusion of species. also, the higher gradient confirms the presence of k-h instability which leads to the breakdown of vortical structures along the shear layer that facilitates the mixing process by entraining fluid from outside to the core region. the qualitative inspection of the flow field suggests the presence of quasi-two-dimensional roller type structures for the planar jet case. to further investigate the nature of coherent vortices “proper orthogonal decomposition” and “dynamic mode decomposition” are invoked. these modal decomposition techniques shed light into the spatial and temporal coherence. this exercise enlightens us on the role of the coherent motion in the flow and explains the role of the lip thickness at the strut base. similarly, the effect of three-dimensionality is investigated for both the strut at mc=1.4 by employing the multi-jet configuration distributed along the span-wise direction. the jet spacing between the square jets is varied to study the effect of the three-dimensionality. however, the study yields that local two-dimensionality in the near jet region had the positive impact on the near-field mixing. for the lowest jet spacing (two times jet height) the results were close to that of the planar jet arrangement.