2 Aerodynamics
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Fig. 2.73 Supersonic aircraft shock system (360doc.com) Mach disk
theory, calculation, and experimental technology of hypersonic aerodynamics
have developed rapidly. Hypersonic flow is generally defined as a flow with
a velocity more than five times that of sound, i.e., Ma ∞ > 5. In fact, this
definition is not absolute. Whether the flow is hypersonic or not depends
on the specific shape of the aircraft. For the flow around a blunt body, the
characteristics of hypersonic flow begin when the Ma ∞ number is greater
than 3; for the flow around a slender body, the hypersonic flow begins when
the Ma ∞ number is greater than 10. The main problems of hypersonic aerodynamics are aerodynamic force (lift, drag, moment, pressure distribution,
etc.), aerodynamic heat (heat flow calculation, heat release measures, etc.),
and aerodynamic physics (photoelectric characteristics of flow field). The
main means of research are theoretical analysis, numerical calculation, and
wind tunnel test. The main parameters of hypersonic flow simulation include
the free flow Mach number, Reynolds number, total flow enthalpy, density