Akira Takano

Low-Reynolds-number flow past an elliptic cylinder

The primary objective of this paper is to obtain the detailed description of the flow field near an elliptic cylinder that is placed perpendicularly in a uniform stream at low Reynolds number. Attention is paid to the shape effects due to the flattening of the cylinder and to the inertial effects of the fluid. The analysis resorts to the method of matched asymptotic expansions. The main part of the inner expansion describes the near flow field as a Stokes flow, which is characterized by the singularities arranged at the two foci of the ellipse. The first three terms

The propagation of reacting blast waves through inert particle clouds

O({\mathbb R}) ({\mathbb R}

Recent efforts toward the minimization of GTO objects and its practices in NASDA

= Reynolds number) in the inner expansion are developed, and the flow aspects under the influence of the fluid inertia are investigated. The streamline patterns with one or two vortices round a finite flat plate of zero thickness, which is a special case of the elliptic cylinder, are presented.

Flow around Rectangular Cylinders

Abstract The purpose of our study is to investigate the gasdynamic aspects of the blast waves in a combustible gas containing small solid suspended particles which are chemically inert. The effects of suspended particles on the reacting blast waves are examined under the assumption that the velocity and temperature of the particles are equal to that of the gas. The two-phase flow equations for the explosion are solved for the spherical case by a series expansion method in the dimensionless chemical heat release. The wave structures and dimensionless propagation velocities are shown. It is found that the suspended particles cause more rapid decay in the propagation velocity of the blast wave by providing heat and momentum sinks.

Wind tunnel experiments for the rectangular cylinders arranged on the ground plate

Abstract For the safety of space activities, minimization of orbital life of the mission-terminated upper stages has been a matter of concern to NASDA. With the advent of the H-II launch vehicle, active measures to decrease orbital life by the low thrust firing of the second stage in a quasi-retrograde direction to lower the perigee height has become possible. In test flights Nos. 2 and 3 of the H-II which have been conducted in 1994 and 1995 for the geostationary mission, this reduced thrust firing of the second stage engine, called “idle mode burn” has been conducted. In test flight No. 2, more than 100 km perigee height reduction was obtained. As a result, orbital life was reduced to about 7 months. This paper outlines the concept of perigee height reduction together with some analytical results for the evaluation of Iuni-solar perturbation effects on the orbital life of objects on geostationary transfer orbit.