Distinctive features of the transonic flow past a cone-cylinder body at small angles of the bend in the body generator at the leading corner edge

Abstract

The distinctive features of the transonic flow past cone-cylinder bodies with small angles of the bend in the body generator at the leading corner edge are considered. The mechanism of transonic flow restructuring downstream of the edge and the associated variation of the gasdynamic parameters are studied, the reasons for the formation of aerodynamic hysteresis are established, and the effect of the length of the cylindrical part of the body is determined.

Wave disturbances in transonic separated flows

“…1) in a near-critical regime (M ∞ ≈ 0.885, α = 6 • , leeward side). In this case, the terminating shock located on the cylindrical surface of the body was normal, while the shock-generated separation zone was developed [2] (Fig. 3a).…”

“…The value and the sign of the phase velocity U f , where U f = −(X j − X i )/(∂ θ/∂ f ), determined for a known distance X j − X i between the points at which the derivative ∂ θ/∂ f is considered (θ is measured in radians), confirm this fact. It was shown that for transonic freestream velocities and a developed state of the free separation zone [2] one of the regions characterizes the propagation of traveling acoustic waves behind the terminating shock. In this region, the phase velocity generally ranges from 2 to 20 m/s.…”

“…The unsteady process arising in the critical stage of transonic flow restructuring, that is, on transition of the free separation zone to the local state [2], is characterized by considerable pressure fluctuations which also occur at low frequencies (on the Sh ≤ 0.1 range). The occurrence of these fluctuations leads to additional growth of the spectral density level and coherence function on the low-frequency range, as well When a supersonic velocity is reached on the free boundary of the separation zone and in its wake, the pressure fluctuation correlation decreases sharply.…”

“…In the process of considering the distinctive features of the flow past oversized cone-cylinder bodies (see Fig. 1 and Table) the notion of the nature of transonic separated flows was further developed [1][2][3][4][5][6][7]. First, the presence of wave disturbances in the subcritical flow regime was established from flow shadowgraphs (Figs.…”

“…First, the presence of wave disturbances in the subcritical flow regime was established from flow shadowgraphs (Figs. 2 and 3) [1,2]. The animation of computer-processed images made it possible to trace the direction of motion of the wave disturbances in space and evaluate their propagation velocity [5,6].…”