Drag Behavior of Inflatable Reentry Vehicle in Transonic Regime

Abstract

The drag coefficient for inflatable reentry vehicles shows discrepancies between a wind tunnel experiment and a flight test in a transonic regime. These discrepancies exist in the drag decrease behavior in the transonic regime and local minimum values of drag above the sonic speed in a wind tunnel. Hence, the present paper focuses on uncovering the reasons and mechanisms behind the same and investigates transonic flow fields around a vehicle by using a transonic wind tunnel and the computational fluid dynamics (CFD) approach. Several test models with diameters ranging from 56 to 96 mm are used to quantitatively evaluate the effects of scale and a sting attached on the rear. Aerodynamic coefficients, pressures at the rear of the model, and density gradient distributions are measured for operation conditions of free-stream Mach numbers ranging between 0.8 and 1.3. In addition, detailed distributions of the flow field properties are clarified using the CFD method, which is validated by the experimental data. The results indicate that a sting behind the test models reduces the steep drag decrease at transonic speeds and that shock waves reflected on the test-section walls of the wind tunnel result in local minimum values at supersonic speeds.

Simulation and analysis of drag for inflatable aerodynamic decelerator

“…There was an obvious expansion wave that appeared in front of the IAD (Figure 4(a)) at Ma = 1, while an obvious bow shock appeared in front of the IAD (Figure 4(b-c)) when the Ma was 3 and 4.5. These were consistent with the wind tunnel experimental results in the literature [12]. With the increase of the cone angle, the pressure of the external flow field increased slightly at Ma = 1 (Figures 4 (b)(e)(f)) and changed nonlinearly.…”

“…The results showed that the drag of the IAD had a significant relationship with its cone angle, and the shape of the IAD would have an influence on the aerodynamic characteristics. Takahashi [12] studied the aerodynamic coefficients of the IAD by transonic wind tunnel experiment and CFD and obtained the mechanism of differences between the above two methods and flight experiments. The results showed that the leeward of the test model affected the drag at the transonic and supersonic regimes.…”

Thermal Aeroelastic Characteristics of Inflatable Reentry Vehicle Experiment (IRVE) in Hypersonic Flow

“…Aimed at these defects, the inflatable reentry vehicle experiment (IRVE) is becoming an emerging technology [1,2]. However, the safety problems of the thermal protection system (TPS) and flexible inflation toroids under hypersonic flow are serious [3,4]. The aerodynamic force will make large deformation and dynamic stress of flexible film [5], and the aeroheating will not only increase the surface temperature of TPS but also induce the thermal expansion of inflation gas [6].…”