Download or read book The Effects of Curvature on Turbulent Mixing Layers written by Chiun Wang and published by . This book was released on 1984 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Curvature and Divergence on Turbulent Mixing Layers written by A. E. Johnson and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Longitudinal Curvature on Turbulent Two stream Mixing Layers written by Michael Walter Plesniak and published by . This book was released on 1989 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Curved Two stream Mixing Layers Part 1 Three dimensional Structure and Part 2 Streamwise Evolution written by Stanford University. Thermosciences Division. Thermosciences Division and published by . This book was released on 1993 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Compressibility Variable Density and Curvature Effects on Turbulent Shear Layers written by Kristen Matsuno and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent mixing layers occur between two streams of fluids with different kinematic and/or thermodynamic properties, and are fundamental flow features which influence the dynamics of a wide variety of applications, ranging from the mixing efficiency of fuel injection in internal combustion to vehicle loads in external aerodynamics. Two motivating applications behind this research include the study of high-speed jets in cross-flow and supersonic retro-propulsion, which occurs as aerospace vehicles use jet plumes to decelerate during entry, descent, and landing. Both these applications are highly influenced by hot jet plumes under highly compressible conditions which exhibit significant streamwise curvature. Simulating the entire flow field associated with such applications is extremely computationally expensive; capturing all important flow features at full resolution is exorbitant for the purposes of engineering design. Thus, grasping the full behavior of turbulent mixing layers in a representative parameter space enables the development of models which can reliably and accurately predict the complex flow fields present in these engineering applications. This work enriches the present understanding of mixing in turbulent shear layers via the systematic inclusion of compressibility, variable density, and streamwise curvature effects. The spreading, or growth rate, of turbulent shear layers is known to decrease with increasing compressibility. Dilatational velocities and pressure-dilatation magnitudes show little contribution to shear layer growth rates, even under highly compressible conditions. A new turbulent length and velocity scale is introduced and shown to scale key turbulent quantities. Inclusion of freestream density variations are also known to decreasing mixing layer growth rates. Trends with increasing compressibility and the importance of mixing layer asymmetry are identified--shear layer centerlines and turbulent stresses in variable density shear layers are biased towards the less-dense freestream, which reduces the turbulent mixing of the mean momentum profile and corresponding growth rates. The combined effects of compressibility and streamwise curvature are demonstrated to be comparable for the selected parameter space. Shear layer growth rates are dominated by the freestream density ratio when streamwise curvature is significant. Changes to model predictions of turbulent growth rates and turbulent kinetic energy levels resulting from various model modifications are evaluated. Reduced accuracy in model predictions of turbulent kinetic energy magnitudes under curved conditions, even with the inclusion of compressibility and curvature modifications, is demonstrated.
Download or read book On Modelling the Effects of Streamline Curvature on Turbulent Shear Flows written by Bassam A. Younis and published by . This book was released on 1984 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Streamline Curvature on Turbulent Flow written by Peter Bradshaw and published by . This book was released on 1973 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Streamline curvature in the plane of the mean shear produces large changes in the turbulence structure of shear layers, usually an order of magnitude more important than normal pressure gradients and other terms in the mean-motion equations for curved flows. The effects on momentum and heat transfer in boundary layers are noticeable on typical wing sections and are very important on highly-cambered turbomachine blades: turbulence may be nearly eliminated on highly-convex surfaces, while on highly-concave surfaces momentum transfer by quasi-steady longitudinal vortices dominates the ordinary turbulence processes. The greatly enhanced mixing rates of swirling jets and the characteristic non-turbulent cores of trailing vortices are also consequences of the effects of streamline curvature on the turbulence structure. A progress report, comprises a review of current knowledge, a discussion of methods of predicting curvature effects, and a presentation of principles for the guidance of future workers.
Download or read book The Effects of Streamwise Concave Curvature on Turbulent Boundary Layer Structure written by Albert H. Jeans and published by . This book was released on 1982 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concave curvature has a relatively large, unpredictable effect on turbulent boundary layers. Some, but not all previous studies suggest that a large-scale, stationary array of counter-rotating vortices exists within the turbulent boundary layer on a concave wall. The objective of the present study was to obtain a qualitative model of the flow field in order to increase our understanding of the underlying physics. A large free-surface water channel was constructed in order to perform a visual study of the flow. Streamwise components of mean velocity and turbulence intensity were measured using a hot film anemometer. The upstream boundary was spanwise uniform with a momentum thickness to radius of curvature of 0.05. Compared to flat wall flow, large-scale, randomly distributed sweeps and ejections were seen in the boundary layer on the concave wall. The sweeps appear to suppress the normal mechanism for turbulence production near the wall by inhibiting the bursting process. The ejections appear to enhance turbulence production in the outer layers as the low speed fluid convected from regions near the wall interacts with the higher speed fluid farther out. The large-scale structures did not occur at fixed spanwise locations, and could not be called roll cells or vortices. (Author).
Download or read book Further Studies of the Curved Turbulent Mixing Layer written by David Margolis and published by . This book was released on 1965 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Engineering Turbulence Modelling and Experiments 3 written by G. Bergeles and published by Newnes. This book was released on 2012-12-02 with total page 932 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents and discussses new developments in the area of turbulence modelling and measurements, with particular emphasis on engineering-related problems. At present, turbulence is one of the key issues in tackling engineering flow problems. Powerful computers and numerical methods are now available for solving the flow equations, but the simulation of turbulence effects which are nearly always important in practice, is still in an unsatisfactory state and introduces considerable uncertainities in the accuracy of CFD calculations. These and other aspects of turbulence modelling and measurements are dealt with in detail by experts in the field. The resulting book is an up-to-date review of the most recent research in this exciting area.
Download or read book Turbulent Shear Flows 7 written by Franz Durst and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Seventh Symposium was held on the campus of Stanford University with·a combination offacilities and weather which made it possible to add open-air poster sessions and coffee breaks to the programme. This was particularly convenient as the call for papers attracted close to three hundred abstracts and a total number of participants well in excess of this number. Some one hundred and thirty papers were presented in carefully phased parallel sessions and thirty six further contributions were made available in the form of posters. In addition, a lively open-forum session allowed additional speakers to make brief presentations. The staff of the Thermo-Sciences Division of the Department of Mechanical Engineering at Stanford undertook the local arrangements with evident success and their extensive record of contributions to Turbulent Shear Flows made the venue particularly appropriate. Also, the Centre for Turbulence Studies, based on the faculty of the University and the NASA Ames Research Center, provided a considerable body of expertise with emphasis on direct numerical stimulation.
Download or read book Prediction of the Effects of Longitudinal Wall Curvature and System Rotation on Turbulent Boundary Layers written by S. A. Eide and published by . This book was released on 1974 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Concave Curvature on Turbulent Boundary Layer Structure written by Albert Hua Jeans and published by . This book was released on 1982 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Compressible Turbulent Mixing written by and published by . This book was released on 1992 with total page 638 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Mixing in Nonreactive and Reactive Flows written by S. Murthy and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence, mixing and the mutual interaction of turbulence and chemistry continue to remain perplexing and impregnable in the fron tiers of fluid mechanics. The past ten years have brought enormous advances in computers and computational techniques on the one hand and in measurements and data processing on the other. The impact of such capabilities has led to a revolution both in the understanding of the structure of turbulence as well as in the predictive methods for application in technology. The early ideas on turbulence being an array of complicated phenomena and having some form of reasonably strong coherent struc ture have become well substantiated in recent experimental work. We are still at the very beginning of understanding all of the aspects of such coherence and of the possibilities of incorporating such structure into the analytical models for even those cases where the thin shear layer approximation may be valid. Nevertheless a distinguished body of "eddy chasers" has come into existence. The structure of mixing layers which has been studied for some years in terms of correlations and spectral analysis is also getting better understood. Both probability concepts such as intermittency and conditional sampling as well as the concept of large scale structure and the associated strain seem to indicate possibilities of distinguishing and synthesizing 'engulfment' and molecular mixing.
Download or read book Transverse Curvature Effects in Turbulent Boundary Layers written by P.M. Sforza and published by . This book was released on 1987 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of Longitudinal Curvature Effects in Turbulent Boundary Layers with Application to Drag Reduction written by A. J. Smits and published by . This book was released on 1985 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work was concerned with a study of subsonic boundary layer behavior downstream of a 90 degree convex bend with a boundary layer thickness of radius-of-curvature ratio of approximately 0.1. Only mean flow results are available. They indicate that the boundary layer, severely distorted when it exits from the curved region, experiences several stages in the recovery process as it relaxes on the flat plate. These stages are described in detail. Keywords: Turbulence.
