This paper presents a phenomenological analysis of a circular jet for an incompressible fluid in the self-preserving flow region. In the eddy viscosity expression: νT∞|υ||ι|, where υ means turbulent velocity component normal to the jet axis and l a kind of Inixing length, |υ| is assumed to be proportional to √υυ2and |l| to the integral scale of turbulence Λg. Expressing them approximately by simple functions so as to simulate the measurements, mean velocity distributions are satisfactorily calculated. In applying the same approach to an axisymmetric far wake flow, simple expressions for the mean velocity defect are obtained, which prooved to be good empirical formulae for the mean velocity distributions of a circular jet. Considerations are also made about the scalar properties like heat and concentration.
Some shapes of the splitter in the wall-attachment fluid amplifier have been used; that is, the sharp splitter, the cusped splitter, the pentagonal splitter and so on. Although the determination of its shape is very important problem that is related with the stability of the jet-attachment, only a few experimental results are reported. And the relation between the shape of the splitteredge and the internal flow field in the fluid amplifier is not clarified in detail. Flow fields in the wall-attachment fluid amplifier are numerically analysed by the finite element method. The distribution of the velocity and the pressure in the amplifier are calculated. And empirical knowledges on the shape of the splitter are reviewed from a point of the velocity distribution and the pressure one. Moreover, it is the purpose of this study to establish the foundation in order to determine the optimum shape of the splitter in the wall-attachment fluid amplifier.
This paper presents the results of an investigation for the jet tab effect in the nozzle flow. The three dimensional inviscid flowfield through the nozzle with the tab inserted into the exhaust stream is computed by the finite difference procedure due to LAX. For various blockage area ratio, the lateral and axial forces for the thrust vector control are obtained by integrating the pressures over the nozzle wall and around the tab and the efficiency of tabs (side thrust/loss in axial thrust) is discussed. The results show that the efficiency of the tab which covers the wall of about 47% in the meridian direction at the nozzle exit is the highest, the side thrust is dependent on the tab width and thickness as well as the blockage ratio and the loss in axial thrust is decreased with the increase of tab width.
A theoretical analysis is presented on the supersonic flutter characteristics of flat isotropic and orthotropic rectangular panels having clamped edges. Modified piston theory is employed for the aerodynamic forces and GALERKIN's method is used. The panel are subjected to midplane normal and shear stresses, and the principal direction of orthotropy and the derection of airflow are assumed to be independent of the panel edges. Stability boundaries are computed and expressed as curves in flutter parameter versus midplane stress plane for both isotropic and orthotropic panels. These results show that the shear stress raise the flutter boundary for certain direction of airflow for both isotropic and orthotropic panels. All calculations are based on a panellength-width ratio of 1.5 and the four modes approximation.
Optimal lamination structure is obtained for laminated plates with simply supported or clamped edges under compressive loads. First, bending-extension coupling is shown to reduce buckling load of laminated plates, and symmetric laminated plates are found to be better than unsymmetric ones from the point of optimization. Next, optimal lamination of symmetric laminated plates is examined by introducing invariants of stiffnesses and two lamination parameters α, β. It is shown that optimal lamination exists in angle-ply laminates for simply supported plates and in either angle-ply or crossply laminates for clamped ones.
By means of optical absorption on the lines AI8103 and AI8014, population densities of 4s[3/2]1 (resonance state) and 4s[3/2]2 (metastable state) were measured in a freely expanding argon plasma. A difference between the axial distributions of the population densities of these states was observed. It was confirmed that these states were not populated in according to the SAHA equilibrium with free electrons and to the BOLTZMANN equilibrium with the levels 5p and