In general, it is well known that the wind force acting on a circular cylinder undergoes a sudden fall of drag under the influence of REYNOLD's number. And it is also assumed that the mean lift does not act on a circular cylinder placed rectangularly in smooth flows. BEARMAN pointed out, however, that the base pressure was discontinuous in the case of a sudden decline of drag in critical REYNOLD'S region. He also indicates a large lift-coefficient (CL=1.3), which is calculated from the pressure distribution of the surface of a circular cylinder. Taking the above into consideration, we attempted to explicate the evolution mechanism of lift-coefficient in critical REYNOLD'S region. Four kinds of cylinders with various diameters were used for the measurement. The measuring range extends from 3.0×104 to 1.0×106 in REYNOLD, S number. In experiments, not only the drag and lift were synchronously measured for four kinds of the circular cylinders each by means of a three-component-balance, but also vortexes were measured at the rear of the circular cylinders by a hot-wire-anemometer. And also the pressure distribution of the surface of the circular cylinder with a diameter of 21.8cm was measured at three points: subcritical region (3.0×104<Re<3.5×105), critical region (3.5×105<Re<5.0×105), supercritical region (5.0×105<Re<1.0×106). As a result of these, we confirmed the evolution of a extremely large lift-coefficient in critical region: (3.5×105<Re<5.0×105) in REYNOLD'S number. This phenomenon was also confirmed from the pressure distribution of the cylinder surface. In the measurement by the hot-wire, furthermore, the spectra of slip streams of cylinders and the discontinuity of the base pressure are very much in agreement with BEARMAN's results.
This paper was planned in order to make clear the wake interaction in a tarbomachine. The analysis of the unsteady force on a cambered blade with angle of attack moving through sinusoidal gusts has been extended to a form suitable for arbitrary gust patterns. An attempt has been made to predict the unsteady force on a cascade blade due to an upstream moving cylinder. In this case, the unsteady force can be considered as owing to the wake effect, the cylinder-thickness effect and the neighboring blade effect. The computed results were given graphically for each effect respectively.
Although curved jets have been treated analytically by several authors from the viewpoint of similar solutions, a jet along a circular arc often appearing in practical applications seems to remain unsolved. The purpose of this paper is to solve such a non-similar flow field of an incompressible turbulent plane jet. Applying the approximation of boundary layer type, an integrated form of the vorticity equation, referred to an orthogonal curvilinear coordinate system, retains only the shear stress terms, as represented by the SAWYER'S expression. The small perturbation method, used by TANI for the first time to the boundary layer problem along a curved wall, is extended to solve a laminar curved jet by the present authors in the preceding paper. In this method, the perturbation parameter, which is the small ratio of the jet width to the radius of curvature of the zerostreamline, is expressed by a power function of the stream-wise coordinate, providing the desired solution in the case of constant pressure across the jet. Non-similar velocity distributions are calculated along several planes normal to the zero-streamline, and it is found, as observed by SAWYER, that the total entrainment rate of the jet is strictly identical to and the total jet spread rate is almost identical to those of a symmetrical jet, and that the velocity profiles of the curved jet are nearly symmetrical.
This paper analyzes more precisely the stiffness of the panels with stringers. In this case cooperation and interaction between panels and stringers should be treated with adequate consideration. Especially in large deformation cases attention has to be paid to nonlinearity. Usually these kinds of stiffened panels have the offset between reference plane of plate and centroidal axis of stringer. As the method we assume functions of membrane stresses and deflections, which satisfy equilibrium equations and boundary conditions, then formulate the incremental equations by the principle of virtual work. By the way of example the panel with a stringer is analyzed. The edges of the plate normal to a stringer and the ends of the beam are assumed to be clamped, the other opposite edges of the plate simply supported. As a result we can treat the effects of flexural, torsional rigidity and offset of stringer, and make clear complicated nonlinearity of these types of structures.