An Investigation of the Characteristics of Swirling Flow in a Diverging Tube


Book Description

The effect of an imposed pressure gradient on the core of a vortex is examined both theoretically and experimentally. The test apparatus consisted of a vortex chamber and a diverging tube. The swirling flow was generated by means of adjustable vanes at the periphery of the vortex chamber and by introducing varying amounts of air. Pressure distributions were obtained along the wall of the tube for various flows and vane settings. In addition, the core of the vortex was photographed by introducing smoke at the axis of the vortex chamber. The theoretical and experimental results show the existence of standing waves arising from the vortex breakdown and the existence of critical conditions, depending on the ratio of the rotational and longitudinal velocity components, beyond which drastic changes of flow structure must occur. The theoretical results were found to be closely related to the observed phenomena. (Author).







An Experimental Investigation of the Effect of Adverse Pressure Gradient on Vortex Breakdown


Book Description

The results of an experimental investigation of the effect of adverse pressure gradient on the vortex breakdown phenomenon in a diverging tube are presented. Adverse pressure gradient was found to be as significant in determining the breakdown position as were the previously known parameters of Reynolds and circulation numbers. An approximate momentum analysis for predicting the vortex breakdown position was carried out which appears to hold promise as a breakdown predictor. (Modified author abstract).




An Experimental Investigation of the Vortex-breakdown Phenomenon


Book Description

The results of an experimental investigation of the characteristics of stationary and travelling vortex breakdowns in swirling flow in a diverging cylindrical tube are presented and discussed. Basically, three types of vortex breakdown were observed, viz., double helix, spiral, and axisymmetric breakdown. The type and location of the stationary breakdowns were found to be dependent upon the Reynolds and circulation numbers of the flow. The breakdown bubble responded to gradual and abrupt changes in the upstream and downstream flow conditions in a manner analogous to the hydraulic jump in open-channel flow. The observations reported and the evidence presented revealed unmistakably that the vortex breakdown is a finite transition from a uniform state of swirling flow (supercritical) to one (subcritical) featuring a large standing wave, followed by standing wavelets, of finite amplitude. (Author).




The Dynamics of Rotating Fluids


Book Description

This textbook on rotating fluid dynamics combines a pedagogical development of theoretical ideas with a description and analysis of many of the fascinating examples of rotating flows found in nature. The book is self-contained, starting in Part I with introductory chapters on fluid dynamics and waves. The largest section of the book is Part II, where a broad theoretical framework is developed for rotating flows, including Ekman layers, inertial waves, Taylor columns, Rossby waves, precession, instabilities, rotating convection, vortex breakdown, and rotating turbulence. The book ends, in Part III, with an analysis of some naturally occurring rotating flows, including tornadoes and dust devils, tidal vortices, tropical cyclones, convection in planetary cores, zonal winds in planetary atmospheres, and astrophysical accretion discs. Davidson presents a unique combination of a deep but broad theoretical framework with a detailed discussion of many naturally occurring flows. Moreover, the book places great emphasis on the pedagogical development of theoretical ideas and the physical insight that brings.




Mathematical Approaches in Hydrodynamics


Book Description

To honor Professor Marshall P. Tulin on his 65th birthday (March 14, 1991), fluid mechanicians and applied mathematicians who have had close association and collaborated with Tulin during his career contribute papers in various areas related to his main interest naval hydrodynamics. No index. Annota