In the present study, numerical simulations were performed and compared with experimental results for transonic and supersonic flows past a cone-cylinder and a spherically blunted cone-cylinder. An axisymmetric numerical code was applied to solve the flow around a cone-cylinder, where Roe's flux difference splitting with MUSCL-type approach for higher order was employed. It was confirmed that it produced sufficient accuracy for the present problem. As a result of applying this method to the flow around a spherically blunted cone-cylinder, a weak recompression wave could be successfully captured on the cone. Furthermore, the effect of curvature radius for forebody on the drag coefficient was examined. Consequently, it was found that the drag coefficient is unexpectedly insensitive to the curvature radius at a Mach number of 1.4 although it takes a minimum value at the ratio of curvature to cylinder radius. r/R=0.4. On the other hand it showed rapid increase at r/R<0.4 for Mach number of 1.9.
The effects of angle of attack α on viscous hypersonic flowfield over a flat plate with a slightly blunt leading edge were examined theoretically and experimentally. An analytical solution which includes the effects of the slight bluntness and of α was obtained by using blast wave theory. It was compared with the experimental shock shape. The change of drag coefficient CD for the blunt leading edge must be considered for small Reynolds number Red which is based on the characteristic dimension of the bluntness d because of the viscous effects there. Taking account of this, qualitative trends of the two were in good agreement. At small α, the shock shape is dominated by the effects of the bluntness. At large α, the strong effects of α make the shock shape straight downstream.
The unstable motions of cellular flames have been investigated using numerical calculation. When the Lewis number is unity (the hydrodynamic effects and the body-force effects are dominant), the stationary cellular flames are predicted. When the Lewis number is smaller than unity (the diffusive-thermal effects are dominant), the transverse propagation of the cell in the flame is predicted, which is actually observed in the experiments. The lateral motion of the cell is due to the diffusive-thermal effects.
Design methodologies of state feedback control are discussed for general dynamical systems including nonlinear systems. The control design is formulated as a nonlinear programming problem to minimize a certain objective function. Strategies for the selection of objective functions are discussed, and the design methodologies are compared with conventional optimal control problems. Stability analysis of the feedback system and computational techniques of the control law are also discussed. An interpolation technique is employed to compute the control input on line, and is examined in a numerical example.
The maximum range of a human-powered aircraft in steady descending flight is studied using the parabolic as well as the experimental drag-polar curves. The aircrafts assumed to have not enough power to sustain steady level flights and the results are compared with those of the powerless gliding flights. The effects of winds and the proximity to the ground surfaces on the maximum flight range are also discussed.
A component mode synthesis technique based on experimentally determined modal parameters is applied to the solar array paddle of Engineering Test Satellite-VI. The paddle structure is divided into four parts and six flexible connective parts. In the synthesis, the measured frequencies are modified by the gravity and atmospheric effects.