The non-viscous swirling flow of an incompressible fluid is analyzed for a circular pipe with arbitrary form of meridian section. When the deformation of the pipe from a circular cylinder is sufficiently small, perturbations of the flow can be assumed to be small comparing with the basic swirling flow, which has constant axial velocity and constant axial angular velocity. Applying the perturbation theory referred to a transformed coordinate, the first and second order solutions are obtained in the present analysis. It is shown that CHOW's solution is comparable with the first order solution and that other conditions for blocking than CHOW's solution are possible. By the use of an inverse method, it can be proved that the present solution is more accurate than the first order solutions.
Because of their high specific strength and stiffness, filament-wound composite materials have been used in weight critical structural members such as rocket motors. An analytical method to predict the fracture strength of filament-wound cylindrical tube under axial compression is proposed. That is, the threedimensional stress components referring to the plane including fibers are analysed taking account of the elastic failure prior to the overall fracture and are then compared with the fundamental strengths corresponding to the four kinds of fracture mechanisms of unidirectional fiberreinforced composites. Axial compression testson reinforced plastic tubes which are helically wound byg lassfibers show a good agreement with the predicted fracture strength and fracture behaviors. Together with the results already described on the fractures of filament-wound tubes under axial tension, torsion, internal pressure and rotation, the proposed method is found to be useful for the optimum design of filamentwound structures.
A simple pressure-measuring system composed of a short circular tube and a small cavity is used for pressure measurement in a test section of a short-duration wind tunnel such as a gun tunnel. The analytical and experimental studies of the response time for the pressure-measuring system are done by concentrating on the length of a pressure leading tube. The present analytical method to determine the response time is based on the numerical results of pressure decrease along a tube obtained by PRESLER. The numerical results of the pressure drop are determined by the steady compressible momelltum and energy boundary-layer equationls and the compressible continuity equation for laminar flow in a heated tube. Taking into account the effect of flow development at the entrance of the tube, the present method is extended to predict the response time of a pressure-measuring system having a wider range of tube length. Excellent correlation is obtained between the numerical and experimental results of the response time along the whole range of tube lengths and supply pressures. The experimental results were obtained under the following conditions: the pressure leading tubes are about 1mm in diameter and 3 to 30mm in length; the supply pressure at the tube inlet iS 2-760 mmHg; and the supplied air and system wall temperatures are 293° K. The experimental results of local total pressure in the shock tunnel is also shown as an example of the application of this method to a hypersonic wind tunnel experiment.
A spherical particle which is illuminated by a light beam in an infinite expanse of a uniform gas is considered. The flow induced around the particle and the force acting on it are investigated for small Knudsen number (the mean free path of the gas molecules divided by the radius of the particle) on the basis of the asymptotic theory for Boltzmann equation. The velocity of steady motion of the particle in the absence of any constraint is also obtained.
The random vibration of cantilever and both ends clamped beams was experimentally studied. The test models were clamped on an electromagnetic shaker and were randomly excited under an approximately band-limited white noise of acceleration. The auto-correlation and power spectral density of the bending strain were obtained through a real time digital anto-correlator and a Fourier transformer. For the nonlinear response of a both ends clamped beam in both cases of flat and buckled states, good agreement was observed between experimental results and theoretical results by the Fokker-Planck equation in one mode approximation. The effect of non-linear response on the anto-correlation and power spectral density is also shown.