The stick-slip problem for a round jet

Summary The stick-slip problem for a round jet studied in Part I gives a good approximation for the swell of a low speed jet when the surface tension is large but it fails when the surface tension is small. In this paper a new stick-slip problem (II) is defined and solved using matched eigenfunction expansions. The new problem reduces to that solved in Part I when the surface tension is large and gives good results in the case of zero and small surface tension.With 18 figures     

On a bound for deformations in terms of Strains in an elastic cylinder

Consider a long thin isotropic elastic cylinder with a self-equilibrated loading on each end face, but which is stress-free on the sides and which has no internal body forces. It is shown that if the displacement gradient is pointwise sufficiently small, then, in any subcylinder of length 1/4a, it is possible to add a rigid body motion such that the L ₂ norm of the resulting displacement gradient can be bounded by a constant times the L ₂ norm of the strain in a subcyclinder of length 2a centered at the same point. The parameter a depends upon the pointwise bound for the displacement gradient (the smaller the bound, the larger a can be) and the constant is independent of the length thickness ratio of the subcylinder.     

Subsonic jet aeroacoustics: associating experiment,modelling and simulation

An overview of jet noise research is presented wherein the principal movements in the field are traced since its beginnings. Particular attention is paid to the evolution of our understanding of what we call a “source mechanism” in free shear flows; to the theoretical, experimental and numerical studies which have nurtured this understanding; and to the currently unresolved conceptual difficulties which render analysis of experimental and numerical data so difficult. As it is clear that accelerated progress in this field of research can be made possible by a more effective synergy between the theoretical, experimental and numerical disciplines—one which draws in particular on the impressive recent progress in experimental and numerical techniques—we endeavour to elucidate the various “source” characteristics identified by these different means of study; the points on which the studies agree or disagree, and the significance of such accord or discord; and, the new analysis possibilities which can now be realised by effectively associating experiment, modelling and simulation.

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Composite power law holdup correlations in horizontal pipes

A wide range of experimental holdup data, from different sources, are analyzed based on a theoretical model proposed in this work to evaluate the holdup in horizontal pipes. 2276 gas–liquid flow experiments in horizontal pipelines with a wide range of operational conditions and fluid properties are included in the database. The experiments are classified by mixture Reynolds number ranges and composite analytical expressions for the relationship between the liquid holdup and no-slip liquid holdup vs. the gas–liquid volumetric flow rate are obtained by fitting the data with logistic dose curves. The Reynolds number appropriate to classify the experimental data for gas–liquid flows in horizontal pipes is based on the mixture velocity and the liquid kinematic viscosity. Composite power law holdup correlations for flows sorted by flow pattern are also obtained. Error estimates for the predicted vs. measured holdup correlations together with standard deviation for each correlation are presented. The accuracy of the correlations developed in this study is compared with the accuracy of 26 previous correlations and models in the literature. Our correlations predict the liquid holdup in horizontal pipes with much greater accuracy than those presented by previous authors.     

A fluidic load cell

A fluidic load cell, based on the fluidic strain-gage concept, was designed, built and tested. The load cell, which employs air as the fluid, can be used to measure forces in electromagnetic fields and high-temperature environments where conventional resistance-strain-gage load cells fail. The load cell built in this survey was tested to 10,000 lb (44.48 kN) in compression. At 10,000-lb compression load, a fluidic pressure change of 425×10^?6 psi (2.93 Pa) was measured. The sensitivity of the system was about 5 percent of the full-scale load and the pressure-load curve was linear. Load cells can be designed for both tension and compression loading and with improvements can be designed to a sensitivity of 1 percent full scale.     

Traveling waves vibrations and buckling of rotating anisotropic shells of revolution by finite elements

A quasi-analytical finite element procedure is developed which can obtain the frequency and buckling eigenvalues of prestressed rotating anisotropic shells of revolution. In addition to the usual centrifugal forces, the rotation effects treated also include the contribution of Coriolis forces. Furthermore, since a nonlinear version of Novoshilov's shell theory is employed to develop the element formulation, the effects of moderately large prestress deflection states can be handled. Due to the generality of solution procedure developed, the axisymmetric prestress states treated can also consist of torque loads. In order to illustrate the procedures capabilities, as well as the significant effects of Coriolis forces, torque prestress and material anisotropy, several numerical experiments are presented.