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Next: Oblique Shock Examples Up: Detached Shock Previous: Detached Shock Index
The issue of maximum deflection has a practical application aside from the obvious configuration used as a typical simple example. In the typical example, a wedge or a cone moves into a still medium or gas flows into it. If the deflection angle exceeds the maximum possible, a detached shock occurs. However, there are configurations in which a detached shock occurs in design and engineers need to take it into consideration. Such configurations seem sometimes at first glance not related to the detached shock issue. Consider, for example, a symmetrical suction section in which the deflection angle is just between the maximum deflection angle and above half of the maximum deflection angle. In this situation, at least two oblique shocks occur and after their interaction is shown in Figure (13.13). No detached shock issues are raised when only the first oblique shock is considered. However, the second oblique shock complicates the situation and the second oblique shock can cause a detached shock. This situation is referred to in the scientific literature as the Mach reflection.
The analysis of this situation is logically very simple, yet the mathematics is somewhat complicated. The maximum deflection angle in this case is, as before, only a function of the upstream Mach number. The calculations for such a case can be carried out by several approaches. It seems that the most straightforward method is the following:
In discussing these issues, one must be aware that there are zones of dual solutions in which sharp shock line coexists with a curved line. In general, this zone increases as Mach number increases. For example, at Mach 5 this zone is . For engineering purposes when the Mach number reaches this value, it can be ignored.
Next: Oblique Shock Examples Up: Detached Shock Previous: Detached Shock Index Created by:Genick Bar-Meir, Ph.D.
On: 2007-11-21 include("aboutPottoProject.php"); ?>