A Mach 3.6 axisymmetric nozzle is designed based on the transition predictions of the nozzle wall boundary layers using the linear stability analysis of Gortler vortices with the eN method. The experimental results of flow quality measurements and boundary layer transition data on a cone in the designed noxzle over a unit Reynolds number range of 4.3-5.9×107/m are presented. The measured transition Reynolds numbers on the cone increase as the wall temperature of the cone decreases. The maximum Reynolds number of 7.7×106/m obtained in the experiment is close to the theoretical predictions of linear stability tkeory. The effects of surface finish of the nozzle wall on the flow qualities and the transition Reynolds numbers on the cone were also observed.
The main purposes of this study are to investigate the effect of strut configurations and isolator length within the engine on the engine performance at Mach 6 condition, and to determine performance of the engine by gas sampling at the exit plane. The sub-scale scramjet engine had an overall length of 2, 100mm, height of 250mm and width of 200mm and was tested at the RamJet engine Test Facility (RJTF) of the Kakuda Research Center, NAL. In the tests were ompared the effects of strut configurations in an engine with a 200-mm long isolator on the engine performance. The thrust as measured along the fuel flow rate, and the fuel distribution at the engine exit plane was measured by means of gas ampling. It was found that the strut configuration had an effect on the thrust performance, that the 200mm-long isolator as effective in preventing combustor/inlet interaction in the engine with full-height strut, and that the fuel distribution in he engine was not uniform which affected the thrust performance. The maximum thrust obtained was 1620 N at the fuel low rate of 70g/s (the bulk equivalence ratio of 0.4).
A Laser-Supported Detonation (LSD) wave can be categorized as one type of hypersonic reacting flows, where exothermicity is supplied not by chemical reaction but by radiation absorption. To clarify the realizability of steady LSD wave and to analyze the real characteristics of LSD propagation, we have numerically simulated the steady 1-D LSD wave propagating through a room-temperature (300K) argon gas, which absorbs CO2 gas dynamic laser, using a 2-temperature model. We have demonstrated the possibility of LSD propagating, using a physical model reflecting, as much as we can, what would occur in a real LSD. Calculated results show that a steady-state LSD wave in which incident laser beam is perfectly absorbed is not sustained by the precursor generated by electron diffusion and that the threshold laser intensity to generate a steady-state LSD wave is reduced when cold gas pressure is increased.
It is desirable that an airpiane couid exert its optimum aerodynamic performance by deforming the wing section to be suitable to the flight conditions. In this paper is presented an analytical calculation of the large deformation of a biconvex wing section and the experiment to confirm the calculated result. The experiment was carried out in a wind tunnel on the biconvex wing model being hollow and of which the outer surface is composed of two elastic curved thin plates. The wing surface is deformed through change of the difference between the outside pressure and the inside pressure of the wing in the air flow by adjusting the inside pressure. The good agreement is obtained between the analytical results and the experimental ones for the contours of the deformed wing sections.
We propose an approach for OTF ambiguity resolution tightly coupled with the DGPS/INS estimator, where we add the states of carrier phase ambiguities and calibrate them along with the INS drift errors. Without any special ambiguity search and testing algorithm, we can resolve the ambiguities by the DGPS/INS estimator and improve navigation accuracy. We also get the improvement of the availability and continuity even though a single frequency GPS receiver is used. This system, named carrier DGPS/INS hybrid navigation system, is evaluated by the theoretical error analysis and flight experiments. Both results show the system enables precise approach and landing under the Category III conditions.