The flow past a delta wing with low aspect ratio at incidence separates from its leading edge. This separation due to fluid viscosity greatly affects the wing performance. In the present paper, the flow over a yawed slender delta wing with leading edge separation is considered. The flow field is approximated by the potential flow model presented by C.E. BROWN and W.H. MICHAEL, Jr., in which each spiral vortex is represented by a line vortex with its strength linearly increasing and also a feeding vortex sheet is added which supplies vorticity from each leading edge to a line vortex on a corresponding side. The calculation is performed in the case of two parameters being small, that is, one of these is the incidence parameter Kα=α/tanδ, the other is the yaw one Kβ=β/tanδ, where α is the incidence angle, β the yaw angle and δ the semi-apex angle of the wing, respectively. It is shown that the leading edge separation on the yawed delta wing leads to interesting wing characteristics and the present method will be very useful as the value of Kα is reduced.
In the wall-reattachment fluid amplifier, by closing the one exit of the channels, the main jet reattach the side wall of the other exit, and the bubble grows on the side wall whose exit is closed. By SCHWARZ-CHRISTOFFEL's transformation, the interior of the amplifier is mapped on the upper part of the other plane, and the analysis is performed for the internal flow by the ideal fluid. The stream lines is obtained on the mapped plane from the complex potentials, and by the transformation of this stream lines, the stream lines in the amplifier is got. In this analysis, the clock-wise vortex is placed to get the reattachment phenomenon, and the counterclock-wise vortex is placed to get the bubble on the non-reattaching side wall.
The oil tracer injection method was applied to measure the velocity profiles of a swirling water flow in the presence of a vortex breakdown. Droplets of kerosene mixed with white paint were used as the tracer particles, and photographs of their loci were taken with the help of a stroboscope in order to determine the velocity. Axial and swirl velocity profiles were measured for three types of vortex breakdown, viz. triangular sheet, axisymmetric and spiral types, from the inlet section of the test pipe to the position of breakdown. It was found that in the cases of the axisymmetric and spiral types the break- down was preceded by an abrupt deceleration near the axis, and was characterized by a stagna- tion point on the axis, while in the triangular sheet case the axial velocity profile was nearly uniform at the position of breakdown. In addition, the type and position of breakdown were observed by color tracer injection method. When the swirl ratio was kept constant at the inlet section of the test pipe, the position of breakdown was found to shift downstream with an increase of the REYNOLDS number.
The lateral-directional motion of an airplane is ordinarily performed by means of coordinated turn (which is one of banked turns and in which the sideslip angle, β, is held zero). The turn of this type has many merits but there is no degree of freedom between airplane's heading and velocity heading because their angular difference is β. Accordingly if we allow β_??_0, the lateraldirectional motion has variety of the combination of airplane's attitude and flight path. In this paper such lateral-directional motions are fully discussed. First we classify the turns according to its attitude, and next the variety written above is shown. Then we pick up a few representative flight modes, and the possibility and the controls required for them about a conventional airplane are examined. Through these a unified and intuitive interpretation is given.