5.2 3-D simulations

3-D computational simulations were also conducted on the scramjet forebody, inlet, and isolator sections. Computational tools used were Fluent and AVUS. In the case of the 3-D Euler computational simulation, a single 3-D stream tube, Figure 13, was exposed to a Mach 6 flow-field. The simulation was first conducted using Fluent, where the process is summarized by Figures 21–23. Examining Figures 22 and 23 demonstrates the use of unstructured grids with clustering in key areas for the analysis. The 3-D simulation required 6.7 million elements, 1,165,267 nodes, and 14.75 GB memory. To aid with visualization, 2-D slices, such as those seen in Figure 24, were extracted for analysis.

implements the dimensionless form of the Navier Stokes equations, and therefore it

The four-point star configuration, Figure 14, was selected as the test case. The

freestream flow-field at a zero angle of attack. Figures 17–19 presents the 2-D Euler simulation results along the centerline of the four point star configuration. On examining these figures, the following observations are made. Figure 17 presents velocity distribution data for the geometry, where it is observed that the behavior of

scramjet forebody-inlet-isolator model was exposed to a Mach 5 hypersonic

the flow imitates the conceptual flow-field presented in Figure 4. That is, freestream flow is first processed by the 2-D oblique shock, travels parallel to the wedge surface, is processed again by the reflected shock and travels parallel to the isolator duct walls. Figures 18 and 19 presents the density and pressure flow-field

reduces the round-off error.

Mach contours at the isolator exit.

Figure 27.

Figure 28.

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Centerline z-component velocity contours.

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5.1.1 2-D Euler simulations using AVUS

A similar process was implemented with AVUS and 2-D slices of flow-field data are extracted and presented in Figures 25–29. On examining these 2-D slices of 3-D data, it is observed that the stream tube is processing the flow in an organized consistent manner that is aligned with its design. Of note are Figures 27–29. Figure 27 examines the z-component of the velocity, and indicated that there is very little cross-flow. Arguable, this is an Euler analysis, however it is worth pointing out that the stream tube 2-D design process holds. This is further supported by Figures 28 and 29 which presents data on the Mach and pressure distribution at the isolator exit.
