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In this paper a novel design method of aerodynamic configuration is proposed to integrate forebody, strut and inlet for strutjet engine, and a model at design point of Mach number 6 is generated to investigate the aerodynamic performance by both simulations and experiments. The basic flow field employed by proposed method is a combined flow named IBB, which is combined by Internal Conical Flow A (ICFA), truncated Busemann flow I (BI) for external section, and truncated Busemann flow II (BII) for internal section. The model configuration is generated by streamline tracing method from basic flow field, in which the forebody section is traced from ICFA and BI flows, and the inlet as well as strut section is traced from BII flow. The simulations in Mach number 4, 5, and 6 demonstrate uniform starting flow fields with relatively high total pressure recovery, which agree well with experiments in wind tunnel. Additionally, in low Mach number cases, this inlet could start at Mach number 3 while it is unstarted at Mach number 2.7; in high Mach number cases, a uniform flow could still exist in Mach number 6.5 while a relatively strong shock wave boundary layer interaction is found in cowl area of Mach number 7 case, indicating the inlet designed by proposed method works in a relatively wide Mach number range.

In this paper, the incident shock–separation shock interactions on a surface plate near the leading edge are studied theoretically and experimentally, and the transition from regular reflection (RR) to Mach reflection (MR) is the main focus. The theoretical method employs free interaction theory (FIT) and the minimum entropy production (MEP) principle to analyse the separation shock strength of flow separated from the boundary layer and separated from the leading edge, respectively, the criterion based on the MEP principle is employed to predict the RR-to-MR transition near the leading edge. The experiments were performed on a rotatable wedge situated over a sharp leading-edge plate such that the wedge could continuously change the flow deflection angle from by means of a high-precision control device. Fast-response transducers and a high-speed camera were used to measure dynamic pressures and to take schlieren images, respectively. The influences of wedge positions, Reynolds numbers and Mach numbers on shock reflections are investigated by careful tests. The theoretical and experimental results for Mach numbers 5, 6, 7 and 8 show good agreement, indicating that the theoretical method is applicable.

The parallel modular inlet is a common configuration in a strutjet engine of the rocket-based combined-cycle hypersonic vehicle. To study the flow interaction between two adjacent inlets, the flowf...

In this paper the configurations of shock wave-boundary layer interactions (SWBLI) are studied theoretically and experimentally in Mach number 2 and 2.5 flows on test models with various wedge angles ranging from to. The proposed theoretical method couples the free interaction theory (FIT) with the minimum entropy production (MEP) principle to predict the appearance of separation shock, resulting in convex, straight and concave separation shock waves according to different solution combinations, which agree well with current experiments. Additionally, several influences on SWBLI are studied experimentally, in which the parameters related to theoretical solutions are found mostly determining the flow configuration, and SWBLI is much more sensitive to incident shock strength than incoming flow properties. Separation could be suppressed by incident shock when the MEP solution is smaller than the FIT, while it could be intensified when the MEP solution is larger than FIT; by contrast, the effects of separation position and model mounting height could be very weak.

In this paper separation-induced shock reflection is studied theoretically and experimentally. An analytical model is proposed to establish the connections among upstream conditions, downstream conditions and shock configurations. Furthermore, the minimum entropy production principle is employed to determine the incident shock angles as well as the criterion for the transition from regular reflection to Mach reflection, which agrees well with experimental results. Additionally, a solution path for a reflected shock that fulfills the minimum entropy production principle is found in the overall regular reflection domain, based on which the steadiest shock configuration may be determined according to upstream and downstream conditions.

The aim of present investigation is to analyze the unsteady oblique shock train and boundary layer interactions during the self-excited and forced oscillation. The oblique shock train is generated in a Mach 2.7 ducted flow and controlled by a downstream elliptical shaft. Cyclic rotating of the shaft leads to the forced oscillation. A Schlieren system as well as transient pressure measurements and particle image velocimetry have been used to capture quantitative and qualitative shock structure information. Results show that the behaviors of unsteady SBLIs structure are highly related to the dynamics of shock motion. For both self-excited oscillation and forced oscillation, the asymmetrical characteristics of first X-shock was found to be negatively correlated with shock velocity. There exist some relative motions between the first X-shock and the second shock, but the absolute variations are very weak. At lower excitation frequency, the relative motion is not noticeable to the oscillation amplitude, it could be treated as a rigid motion in the duct. At higher excitation frequency, the relative motion amplitude is significant to the oscillation amplitude, and the relative movement of shock cells becomes the dominant motion. There is a hysteretic effect and phase lag between the shock position and downstream pressure perturbation when the shock train travels along a different path for upstream and downstream movements, and the hysteretic effect becomes weaker with increasing frequency.

The structure and dynamics of an oblique shock train in a duct model are investigated experimentally in a hypersonic wind tunnel. Measurements of the pressure distribution in front of and across the oblique shock train have been taken and the dynamics of upstream propagation of the oblique shock train have been analyzed from the synchronized schlieren imaging with the dynamic pressure measurements. The formation and propagation of the oblique shock train are initiated by the throttling device at the downstream end of the duct model. Multiple reflected shocks, expansion fans and separated flow bubbles exist in the unthrottled flow, causing three adverse-pressure-gradient phases and three favorable-pressure-gradient phases upstream the oblique shock train. The leading edge of the oblique shock train propagates upstream, and translates to be asymmetric with the increase of backpressure. The upstream propagation rate of the oblique shock train increases rapidly when the leading edge of the oblique shock train encounters the separation bubble near the shock reflection point and the adverse-pressure-gradient phase, while the oblique shock train slow movement when the leading edge of the oblique shock train is in the favorable-pressure-gradient phase for unthrottled flow. The asymmetric flow pattern and oscillatory nature of the oblique shock train are observed throughout the whole upstream propagation process.

A design method employed for preliminary integration of a hypersonic vehicle airframe configuration with its propulsion flow path is described. This method is primarily based on the integration of the variable cross section inward-turning inlet and the airframe. Three typical configurations include lifting body, sim-waverider, and semi-axisymmetric cone. Rectangular-to-circular, erose-to-circular, and sector-to-circular shape transition Busemann inlets are designed to integrate these three vehicle bodies, respectively. The results of numerical simulations show that the aerodynamic performance of these configurations, coupled with the propulsion flow path, inherits the characteristics of their original airframe shapes, such as the high lift/drag ratio of sim-waverider and the low-drag performance of semi-axisymmetric cone configuration. The computed results also demonstrate that the inward-turning inlets integrate smoothly with their respective vehicle airframes and that the design method is viable.