Since the shock wave was a kind of the air compression wave, the larger the shock wave initial overpressure was, the larger the
oblique shock wave pressure generated by the shock wave at pipeline bifurcation was, and the faster the shock wave attenuation was because the energy loss was greater after strong reflection stack of the shock wave.
The 14-X B model lower surface was designed based on the two-dimensional compressible flow (oblique shock wave relationships) and expansion wave (Prandtl-Meyer theory), considering the simplest case, that is, no viscous flow, calorically perfect air ([gamma] = 1.4), and scramjet engine with power off [11].
The static pressure measurements at the lower surface of the 14-X B model are compared with the static pressure evaluated at the same freestream conditions via no viscous flow, calorically perfect air ([gamma] = 1.4) oblique shock wave relationships, and computational fluid dynamics (CFD) simulations using the ANSYS FLUENT software (Figure 9).
The model design parameters are found by solving analytically using governing isentropic flow relations (1) (2) (3), oblique shock wave relations (4) (5) by following the shock-on-lip condition.
Oblique shock waves, expansion waves and shock wave interactions are mainly considered.
As discussed in Figure 4, freestream disturbance wave will be enlarged under the action of shock wave; From Figure 7, it is obtained that the effects of normal shock wave are larger than that of
oblique shock wave on freestream disturbance.
The
oblique shock wave formed over the concave corner of the ramp is shown in fig.
At x = 0.26 m, a strong
oblique shock wave train is formed, which may be caused by a great amount of heat release in this location and the oblique shock wave/boundary layer interaction.
In general, due to the fact that the amplification caused by normal shock wave (approximates) in nose is larger than that caused by
oblique shock wave in nonnose, the amplitude of pressure disturbance in nose is significantly larger than that in nonnose.
The compression ramp is designed to create a series of
oblique shock waves.
If the exit pressure is slightly less than the back pressure, then
oblique shock waves occur at the nozzle exit as shown in figure 2.
