A spherical solid particle with an outer shell in an infinite expanse of a slightly rarefied gas at rest with a uniform temperature gradient is considered. The flow induced around the particle and the force acting on it (thermal force) are investigated on the basis of the asymptotic theory for a slightly rarefied gas. The velocity of steady motion of the particle which is left free in the gas is also obtained. All the results (velocity and temperature of the gas, thermal force, etc.) except the temperature field inside the particle coincide with the corresponding results for a homogeneous sphere with an appropriate thermal conductivity (virtual thermal conductivity), which is determined by the thermal conductivities of the shell and the core and the thickness of the shell.
Application of "coordinates (in-plane) integraltransforms" in order to formulate linearized lifting surface theories (the kernel function method) is demonstrated for both sub-and supersonic three-dimensional inviscid flows. It is found that the streamwise Fourier inverse transform only for the subsonic flow requires some caution: a singular integral brings an arbitrariness which may be determined so that disturbances vanish at infinitely upstream. Apart from this point, coordinates (in-plane) integral transforms make it pure mathematical to formulate the problems and thus physical models or aerodynamicist's experiences become almost useless.
The effect of non-Maxwellian energy distribution for free electrons upon the radiative properties of weakly ionized helium gas has been investigated theoretically and experimentally. In order to obtain the population distribution among the excited levels of the neutral atom, which determines the radiative properties of the plasma, rate equations are solved with the non-Maxwellian electron energy distribution calculated numerically from the Boltzmann equation for the distribution function. It is found that the theoretical population distributions are in good agreement with the experimental ones obtained in the positivecolumn plasma which is typically weakly-ionized, and are largely different from the theoretical ones with the Maxwell electrons.
Semi-microscopic thermal residual stress state in the unidirectional fiber-reinforced composites is experimentally and theoretically investigated. Photo-elastic experiments without external loads are conducted for a plate specimen containing some inclusions like a coin. Temperature dependent properties of the matrix are measured. Because the specimen to be analyzed is such a plate, the constitutive equations should be modified for the plane stress problem. The solution procedure is identical with the one used consistently by the authors. Calculated results based on the temperature dependent matrix properties are in very good agreements with the experimental results except for the areas near the fiber-matrix interface. Estimating calculations of the stress levels in the ordinal unidirectional CFRP are also executed as the first step of the elucidation of the failure behavior.
A lifting-line theory is examined in detail for a wing with a high aspect ratio in the ground effect. Particularly, the method of the asymptotic expansions is applied to the integral equation given by the lifting-surface theory, unlike the method of the matched asymptotic expansions to a differential equation. Furthermore, the integrodifferential equation for a rectangular plane wing is estimated analytically by calculating the distribution of the circulation round a semi-infinite wing of constant chord, and comparison of the lift coefficient with earlier works is carried out.
The subject of modern control theory has received increased interest in recent years, partly because of its importance as an analytical tool for the study of advanced control technology such as CCV, and of the corresponding active control approaches. However, the main disadvantage of the modern control technique is its dependence on the accessibility of all the state variables and parameters of the plant to be controlled or identified. In this report, an adaptive observer scheme is developed to estimate the state vector and to identify all the parameters of a single-input single-output n-th order linear system where only the input and output can be observed, and is based on the new canonical form method without LIAPUNOV'S direct method. The approach is proved to be asymptotically stable and thus ensuring the convergence of the identification algorithm. Numerical computations are done for the parameter identification and state estimation problems of VTOL aircraft and for the synthesis of a state feedback controller.