Experimental Measurements of Starting Loads and Model Behaviors in the Indraft Supersonic Wind Tunnel

Measurements of starting load in the indraft supersonic wind tunnel of Muroran Institute of Technology were conducted for Mach 2, 3 and 4 conditions with the AGARD-B model. The high-speed photographs covering the behaviors of the wind tunnel model from the start to end of the operation were taken. Those photographs make clear that the oscillations of the model coincide with the measured starting load oscillation and starting loads were caused by two shock waves. The first shock wave is the reflection shock, generated at the nozzle throat by expansion wave reflection. The second wave is comprised asymmetric oblique shock waves (AOS) coming from upstream. AOS can generate asymmetric conical shock (ACS) around the nose cone of the model, which would have directly caused the starting loads on the wind tunnel model. Based on these observations, propose a conical shock theory, as an alternative starting load prediction theory instead of the normal shock theory

Drag Reduction on the Basis of the Area Rule of the Small-scale Supersonic Flight Experiment Vehicle Being Developed at Muroran Institute of Technology

A small-scale supersonic flight experiment vehicle (OWASHI) is being developed at Muroran Institute of Technology as a flying testbed for verification of innovative technologies for high speed atmospheric flights which are essential to next-generation aerospace transportation systems. The second-generation configuration M2011 of the vehicle with a single Air Turbo Ramjet Gas-generator-cycle (ATR-GG) engine has been proposed. Its transonic thrust margin has been predicted to be insufficient, therefore drag reduction in the transonic regime is quite crucial for attainability of supersonic flights. In this study, we propose configuration modifications for drag reduction on the basis of the so-called area rule, and assess their effects through wave drag analysis, wind tunnel tests, and CFD analysis. As a result, the area-rule-based configurations have less drag than the baseline configuration M2011. However, the effects of the proposed bottleneck on the fuselage below the main wing are smaller than predicted. It would be caused by the drag due to separation and shocks around the bottleneck. It is necessary to redesign the area-rule-based bottleneck to be smoother

Conceptual analysis of Japan\u27s Jovian system exploration: Interplanetary orbits and aeroassistance in the Jovian atmosphere

The Galileo spacecraft exploration has shown a probability that Europa has a large amount of water under its icy surface, as well as that some kinds of life may be present on Europa. In the present study, feasibility analysis for Japan\u27s Europa exploration is carried out in terms of interplanetary and Jupiter atmospheric flight trajectories. First, three types of interplanetary trajectories from the Earth to Jupiter, i.e. direct, Mars gravity-assisted, and Venus-Earth gravity-assisted, are calculated and the case of the minimum Jovian insertion energy, i.e. the maximum deliverable mass, is selected in each type of the trajectories. Second, flight trajectories in the Jovian atmosphere for decelerating and deploying spacecraft to Europa are calculated and the required mass of the ablator is evaluated. It is clearly shown that aerobraking is much more advantageous for enhancement of deliverable mass than applying chemical propulsion alone, and that the combination of H-IIA Augmented Launch Vehicle, gravity assists, and aerobraking will enable Europa biological explorations

Numerical and experimental investigations on Mach 2 and 4 pseudo-shock waves in a square duct

The structures and characteristics of λ-shaped and X-shaped pseudo-shocks in a square duct are investigated through numerical simulations and experiments at Mach 2 and Mach 4, respectively. The experiments were carried out in a pressure-vacuum supersonic wind tunnel with a test cross section of 80 x 80 mm(2). Numerical simulations were carried out using the Harten-Yee second-order TVD scheme and the Baldwin-Lomax turbulence model. The Reynolds numbers for the Mach 2 and 4 cases were Re-∞ = 2.53 x 10(7) and Re-∞ = 2.36 x 10(7), respectively, and the flow confinement was δ(∞)/h = 0.35 for both cases. The computational results for the Mach 2 pseudo-shock wave are in good agreement with the experimental results. Based on this agreement, the flow quantities, which are very difficult to obtain experimentally, were analyzed by numerical simulation. Although several differences were found between the computational results and experiments in the case of Mach 4 due to asymmetric characteristics in experiment which could not be reproduced in numerical simulation, the computational results are valuable for understanding this complex asymmetric phenomenon