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Shock-wave modes of flow at the inlet to the diffuser of a hypersonic scramjet engine: The effect of flight altitude and velocity

“…The concrete form of dependence (1) and detailed analysis of SP in the case of variation of γ + , γ -, and Mare given in [20,21]. It is restricted by the values of θ min ≤ θ ≤ θ max and ξ min ≤ ξ ≤ ξ max and is mirror-symmetric relative to the straight line θ s = 0.5(θ min + θ max ).…”

“…According to the physics of the process, the former case is realized more frequently: additional degrees of freedom (for example, vibrational) are excited behind the shock, and the value of γ decreases (falling regions of curves in Fig. A detailed description of the model of effective adiabatic exponent, the range of its validity, gasdynamic relations, and the difference from the classical model are given in [18][19][20], and the effect of γ i on the form of SP is investigated in [21]. The latter case is the region of parameters before and behind the shock front, located in the rising regions of curves in Fig.…”

“…The span of polar depends on the value of γ behind the front of incident PS: the lower the value of γ, the larger the width and height of the polar (a detailed investigation was performed in [20,21]). The span of polar depends on the value of γ behind the front of incident PS: the lower the value of γ, the larger the width and height of the polar (a detailed investigation was performed in [20,21]).…”

“…In practical work aimed at developing HSE, this set of parameters is rather an unpleasant feature as regards control system development, because one cannot predict exactly which mode will be realized, in view of the large number of factors affecting this process, including the flow history (for more detail, see [22][23][24] Some numerical results of computer simulation of problems of this type for flight altitudes of 0, 40, and 100 km are given in Table 2. The structure of the table is the same as that of Table 1.…”

“…I use the method of "effective adiabatic exponent" (see [17][18][19]) to investigate the gas-and thermodynamics of physical processes; this method enables one to simulate the flow of gas with due regard for its actual properties by means of variation of the adiabatic exponent γ (p, T) in the entire flow field as a function of local values of pressure p and temperature T. This involves the use of a physicomathematical model of SW with different adiabatic exponents before and after the pressure shock front which is assumed to be an infinitely thin discontinuity. The basic gas-and thermodynamic relations on the discontinuity, results of analysis of the range of validity of the model, and its comparison with the model of invariability of the properties of a gas medium during transition through a PS are given in [20].…”