The use of the Fiber Bragg Grating (FBG) cantilever sensor was attempted for the detection of flow separation. This optical sensor detects a shift of the wavelength of the reflected light corresponding to the amount of strain caused in the optical fiber. We successfully examined the sensing of the direction of flows. In the next stage, this sensor was installed at trailing edge of an aerofoil, to investigate the performance of the sensor and the characteristics of the flow separation. As a result, it is found that this sensor could catch the changing of the flow direction due to flow separation.

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Optimal aircraft maneuver against two missiles are studied. In this paper, the problem is formulated as a nonlinear optimal control problem and solved by the steepest ascent method. In order to maximize the miss distance against two missiles simultaneously, a special type of criterion function is employed by introducing a window function. Some examples obtained by our method show reasonable aircraft optimal controls, and verify the validity of our method. Our method will be applied to pursuit-evasion and collision avoidance problems with multi-vehicles.

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This paper presents a decentralized collision-free path calculation method for multiple UAVs (Unmanned Aerial Vehicles). The developed method, which is composed of force field algorithm for conflict reduction and quadratic programming for path optimization, can execute parallel path calculation. While conventional path calculation methods tend to require prohibitive computational time as the number of concerned aircraft increases, the computational time in the developed method is not so sensitive to the number of concerned aircraft. Results of numerical simulations are presented to demonstrate the reasonableness of resulting paths, the computational efficiency, and robustness of the developed method.

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It is still challenging to predict surface heat-transfer rate in hypersonic flow computations. In this paper, we first performed numerical experiments by changing numerical flux functions and meshes for a hypersonic flow around a hemisphere. Results show that AUSM+ flux function by Liou (1996) on a carefully refined mesh can lead to a shock stable solution with an accurate aerodynamic heating on the surface. Then, a numerical simulation on a hypersonic flow around two bodies involving a shock/shock interaction and a boundary-layer separation has been conducted by using the same method. Although this is a rather difficult problem with a complicated flowfield, comparisons show good agreement with the corresponding experimental data, including the surface heat-transfer rate profile. Therefore, we can say that we have established a numerical method to accurately predict surface heat-transfer in hypersonic shock interacting flows. Finally, detailed analysis of the computed flowfield has been made.

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To explore future RLVs, a hypersonic flowfield around a Two-Stage-To-Orbit (TSTO) configuration is analyzed in this paper. This study also demonstrates how CFD, as a powerful tool, can be applied to investigate such a complex flowfield involving a shock/shock interaction and a boundary-layer separation. First, the hypersonic flow around two bodies of the TSTO model has been numerically simulated, and then, the results are validated by comparing with experimental data taken at the UT-Kashiwa Hypersonic Tunnel. Finally, the detailed, computed flowfield is shown to have pairs of streamwise vortices (including horseshoe vortices) with alternating signs of rotation around the TSTO body surfaces.

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Control to improve control characteristics of aircraft, CA (Control Augmentation), is used to realize the desirable motion of aircraft corresponding to pilot's control action. When the control laws using fuzzy inference were designed, trial and error was repeated for optimization of the parameter. Here, in designing control laws using fuzzy neural networks, the systematic optimization of the parameter was possible using the learning algorithm usually used in neural networks, by expressing the fuzzy inference in the form of neural networks. Here, the control laws, which learned the characteristics of the aircraft for one flight condition only, were used in all flight conditions without changing any parameter. Evaluation of the designed control laws showed good performance in all flight conditions. This proves that fuzzy neural networks are an effective and flexible method when applied to control laws for control augmentation of aircraft.

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This paper reports the spectrum analysis result for turbulence and the induced vertical accelerations of aircraft. The flight data obtained in real flight are analyzed in frequency domain. The obtained power spectrum density of turbulence are compared with a well-known continuous gust model, i.e.\ obreakspace {}Dryden model, and it is confirmed that the Dryden model can represent such turbulence with appropriately defined gains. The dominant frequency range of the induced vertical accelerations is confirmed to be almost less than 0.5 Hz.

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A method is proposed to control the variation of cushion pressure of oscillationg SES (Surface Effect Ship). The peripheral nozzle is attached along the periphery that moves vertically changing the height above the wave surface. The nozzle height is continuously changed in accordance with the motion of the craft. The change of pressure due to the undulation of the traveling surface is compensated by the change of the nozzle height. It has been shown experimentally that the variation of the cushion pressure is effectively controlled adjusting the amplitude and the phase of the vertical motion of the nozzle.

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