Download or read book Direct Numerical Simulations of the Rotating disk Boundary layer Flow written by Ellinor Appelquist and published by . This book was released on 2014 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Instability Transition and Turbulence written by M.Y. Hussaini and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of the Workshop on In stability, Transition and Turbulence, sponsored by the Institute for Computer Applications in Science and Engineering (ICASE) and the NASA Langley Research Center (LaRC), during July 8 to August 2, 1991. This is the second workshop in the series on the subject. The first was held in 1989, and its proceedings were published by Springer-Verlag under the title "Instability and Transition" edited by M. Y. Hussaini and R. G. Voigt. The objectives of these work shops are to i) expose the academic community to current technologically im portant issues of transition and turbulence in shear flows over the entire speed range, ii) acquaint the academic community with the unique combination of theoretical, computational and experimental capabilities at LaRC and foster interaction with these capabilities, and iii) accelerate progress in elucidating the fundamental phenomena of transition and turbulence, leading to improved transition and turbulence modeling in design methodologies. The research areas covered in these proceedings include receptiv ity and roughness, nonlinear theories of transition, numerical simu lation of spatially evolving flows, modelling of transitional and fully turbulent flows as well as some experiments on instability and tran sition. In addition a one-day mini-symposium was held to discuss 1 recent and planned experiments on turbulent flow over a backward facing step.
Download or read book Studies of Turbulent Boundary Layer Flow Through Direct Numerical Simulation by Martin Skote written by Martin Skote and published by . This book was released on 2001 with total page 335 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Direct Numerical Simulation of Boundary layer Flow Over Surface Roughness written by Russell Gerard De Anna and published by . This book was released on 1993 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Direct Numerical Simulation of Turbulent Flow Over a Dimpled Flat Plate Using an Immersed Boundary Technique written by Jeremiah J. Gutierrez-Jensen and published by . This book was released on 2011 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many methods of passive flow control rely on changes to surface morphology. Roughening surfaces to induce boundary layer transition to turbulence and in turn delay separation is a powerful approach to lowering drag on bluff bodies. While the influence in broad terms of how roughness and other means of passive flow control to delay separation on bluff bodies is known, basic mechanisms are not well understood. Of particular interest for the current work is understanding the role of surface dimpling on boundary layers. A computational approach is employed and the study has two main goals. The first is to understand and advance the numerical methodology utilized for the computations. The second is to shed some light on the details of how surface dimples distort boundary layers and cause transition to turbulence. Simulations are performed of the flow over a simplified configuration: the flow of a boundary layer over a dimpled flat plate. The flow is modeled using an immersed boundary as a representation of the dimpled surface along with direct numerical simulation of the Navier-Stokes equations. The dimple geometry used is fixed and is that of a spherical depression in the flat plate with a depth-to-diameter ratio of 0.1. The dimples are arranged in staggered rows separated by spacing of the center of the bottom of the dimples by one diameter in both the spanwise and streamwise dimensions. The simulations are conducted for both two and three staggered rows of dimples. Flow variables are normalized at the inlet by the dimple depth and the Reynolds number is specified as 4000 (based on freestream velocity and inlet boundary layer thickness). First and second order statistics show the turbulent boundary layers correlate well to channel flow and flow of a zero pressure gradient flat plate boundary layers in the viscous sublayer and the buffer layer, but deviates further away from the wall. The forcing of transition to turbulence by the dimples is unlike the transition caused by a naturally transitioning flow, a small perturbation such as trip tape in experimental flows, or noise in the inlet condition for computational flows.
Download or read book Spatial Direct Numerical Simulation of Compressible Boundary Layer Flow written by Bono Wasistho and published by . This book was released on 1997 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling Atmospheric and Oceanic Flows written by Thomas von Larcher and published by John Wiley & Sons. This book was released on 2014-10-30 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling Atmospheric and Oceanic Flows: Insights from Laboratory Experiments and Numerical Simulations provides a broad overview of recent progress in using laboratory experiments and numerical simulations to model atmospheric and oceanic fluid motions. This volume not only surveys novel research topics in laboratory experimentation, but also highlights recent developments in the corresponding computational simulations. As computing power grows exponentially and better numerical codes are developed, the interplay between numerical simulations and laboratory experiments is gaining paramount importance within the scientific community. The lessons learnt from the laboratory–model comparisons in this volume will act as a source of inspiration for the next generation of experiments and simulations. Volume highlights include: Topics pertaining to atmospheric science, climate physics, physical oceanography, marine geology and geophysics Overview of the most advanced experimental and computational research in geophysics Recent developments in numerical simulations of atmospheric and oceanic fluid motion Unique comparative analysis of the experimental and numerical approaches to modeling fluid flow Modeling Atmospheric and Oceanic Flows will be a valuable resource for graduate students, researchers, and professionals in the fields of geophysics, atmospheric sciences, oceanography, climate science, hydrology, and experimental geosciences.
Download or read book Numerical Simulation of Flow Between Two Parallel Co Rotating Discs written by Dr. SMG Akele and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of fluid flow between two rotating discs aims to predict flow characteristics. In this paper numerical simulation is used to investigate axisymmetric swirling flow between two parallel co-rotating discs. Methodology entails, firstly, inputing parameters from CFD software are into previos study developed dimensionless radial velocity model for flow between two discs to obtain dimensional radial velocity of the model. Secondly, previous study parameters are used to perform numerical simulation on laminar and turbulent flows between two parallel co-rotating discs. The numerical simulation results are compared to previous study results. Then comparative numerical simulations was carried out on laminar and turbulent flows using CFD software.Results obtained showed that for the this study dimensional radial velocity and previous study dimensionless radial velocity, radial velocity distribution increase proportionately from the disc surface at 0m/s to 2208.00m/s and 0 to 0.0002396 respectively, at the domain centre. And both results satisfy initial inlet and boundary conditions with resultant parabolic profiles. In the study, it is shown that turbulent flow radial velocity profile is smoother than for laminar flow. The radial velocity increases from 0 at the walls to 0.15m/s before decreasing to - 0.2m/s at the mid-centre for laminar flow while for turbulent flow the radial velocity intitially increases from 0 at the walls to 0.15m/s before decreasing to -0.06m/s at the discs centre; while for laminar flow, swirl velocity decrease from approximately 2.55m/s to 0.55m/s and for turbulent flow the swirl velocity decrease from approximately 2.84m/s to 1.62m/s. The turbulent flow swirl velocity profile seen to be smoother than for laminar flow around the discs centre. The study further showed that for fluid near the discs surfaces radial velocity net momentum is radially towards the outlet with flow laminar in the boundary layer region and the velocity turbulent towards the domain centre. For static pressure, laminar flow maximum and minimum static pressure 2.48pa and -0.033pa respectively, while for turbulent flow maximum and minimum static pressure were 0.00 and -0.0024pa. The developed previous study model can therefore be used to predict radial velocity distribution between steady axisymmetric flow between two parallel co-rotating discs.
Download or read book Direct and Large Eddy Simulation I written by Peter R. Voke and published by Springer Science & Business Media. This book was released on 1994-10-31 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is a truism that turbulence is an unsolved problem, whether in scientific, engin eering or geophysical terms. It is strange that this remains largely the case even though we now know how to solve directly, with the help of sufficiently large and powerful computers, accurate approximations to the equations that govern tur bulent flows. The problem lies not with our numerical approximations but with the size of the computational task and the complexity of the solutions we gen erate, which match the complexity of real turbulence precisely in so far as the computations mimic the real flows. The fact that we can now solve some turbu lence in this limited sense is nevertheless an enormous step towards the goal of full understanding. Direct and large-eddy simulations are these numerical solutions of turbulence. They reproduce with remarkable fidelity the statistical, structural and dynamical properties of physical turbulent and transitional flows, though since the simula tions are necessarily time-dependent and three-dimensional they demand the most advanced computer resources at our disposal. The numerical techniques vary from accurate spectral methods and high-order finite differences to simple finite-volume algorithms derived on the principle of embedding fundamental conservation prop erties in the numerical operations. Genuine direct simulations resolve all the fluid motions fully, and require the highest practical accuracy in their numerical and temporal discretisation. Such simulations have the virtue of great fidelity when carried out carefully, and repre sent a most powerful tool for investigating the processes of transition to turbulence.
Download or read book Advanced Manufacturing Processes written by Volodymyr Tonkonogyi and published by Springer Nature. This book was released on 2020-03-27 with total page 643 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a timely yet comprehensive snapshot of innovative research and developments in the area of manufacturing. It covers a wide range of manufacturing processes, such as cutting, coatings, and grinding, highlighting the advantages provided by the use of new materials and composites, as well as new methods and technologies. It discusses topics in energy generation and pollution prevention. It shows how computational methods and mathematical models have been applied to solve a number of issues in both theoretical and applied research. Based on selected papers presented at the Grabchenko’s International Conference on Advanced Manufacturing Processes (InterPartner-2019), held in Odessa, Ukraine on September 10-13, 2019, this book offers a timely overview and extensive information on trends and technologies in the area of manufacturing, mechanical and materials engineering. It is also intended to facilitate communication and collaboration between different groups working on similar topics, and to offer a bridge between academic and industrial researchers.
Download or read book Boundary Layer Flows written by Vallampati Ramachandra Prasad and published by BoD – Books on Demand. This book was released on 2020-01-22 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by experts in the field, this book, "Boundary Layer Flows - Theory, Applications, and Numerical Methods" provides readers with the opportunity to explore its theoretical and experimental studies and their importance to the nonlinear theory of boundary layer flows, the theory of heat and mass transfer, and the dynamics of fluid. With the theory's importance for a wide variety of applications, applied mathematicians, scientists, and engineers - especially those in fluid dynamics - along with engineers of aeronautics, will undoubtedly welcome this authoritative, up-to-date book.
Download or read book Handbook of Thermal Science and Engineering written by and published by Springer. This book was released on 2018-07-31 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Handbook provides researchers, faculty, design engineers in industrial R&D, and practicing engineers in the field concise treatments of advanced and more-recently established topics in thermal science and engineering, with an important emphasis on micro- and nanosystems, not covered in earlier references on applied thermal science, heat transfer or relevant aspects of mechanical/chemical engineering. Major sections address new developments in heat transfer, transport phenomena, single- and multiphase flows with energy transfer, thermal-bioengineering, thermal radiation, combined mode heat transfer, coupled heat and mass transfer, and energy systems. Energy transport at the macro-scale and micro/nano-scales is also included. The internationally recognized team of authors adopt a consistent and systematic approach and writing style, including ample cross reference among topics, offering readers a user-friendly knowledgebase greater than the sum of its parts, perfect for frequent consultation. The Handbook of Thermal Science and Engineering is ideal for academic and professional readers in the traditional and emerging areas of mechanical engineering, chemical engineering, aerospace engineering, bioengineering, electronics fabrication, energy, and manufacturing concerned with the influence thermal phenomena.
Download or read book Structure and Modeling of the Three Dimensional Boundary Layer on a Rotating Disk Final Report written by and published by . This book was released on 1996 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Almost all practical turbulent flows include three dimensional boundary layers (3DTBL's), and in many cases, the 3DTBL is the dominant feature of the flow. A boundary layer is defined as a thin layer adjacent to the surface in which the velocity drops rapidly from the freestream value to zero at the wall. A 3D boundary layer is one in which the flow direction also changes rapidly approaching the wall. This change in the flow direction called skewing is caused by transverse pressure gradients, centrifugal forces, or motion of the surface. Most research on turbulent boundary layers has been done in simple two dimensional flows in carefully controlled wind tunnels. Such boundary layers are now well understood, and excellent models are available describing both the fluid mechanics and heat transfer behavior. Recent fluid mechanics studies have shown that skewing can have a pronounced effect on the boundary layer turbulence. Models based on eddy-viscosity concepts fail, and more complex stress transport models cannot capture the reduction of turbulent mixing that usually accompanies skewing. It was unknown prior to the present study what effect the skewing might have on turbulent heat transfer. It was suspected that turbulent heat transport would be reduced in analogy to the reductions of turbulent shear stress. It was also unknown how the skewing would effect the turbulent Prandtl number, a quantity which is embedded in most turbulent heat transfer prediction schemes. The objectives of the present study were then to study the surface heat transfer rate and the turbulent heat flux in a simple three dimensional boundary layer. In particular, the research addressed the heat transfer from a heated disk rotating in an otherwise quiescent environment.
Download or read book Turbulent Fluid Friction of Rotating Disks written by P. Cooper and published by . This book was released on 1973 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: The incompressible flow field between two infinite parallel disks, one of them rotating and the other stationary, is analyzed and solved for situations where the radial Reynolds number is large enough to produce turbulent flow. An effective viscosity method is used, the effective viscosity being regarded as a scalar. The validity of the approach is demonstrated for the case of boundary layer development on a rotating disk in an infinite fluid otherwise at rest. An implicit finite-difference method is used to obtain a numerical solution of the boundary layer flow from the axis out to a radius corresponding to R sub e = 10 to the 7th power. For an assumed transition from laminar to turbulent flow at the experimentally observed value of R sub e = 300,000, the resulting skewed velocity profiles and disk friction drag agree with measurements. The case of the surrounding fluid rotating at one-half the disk speed is also solved. The resulting values of drag moment approximate experimental data for enclosed rotating disks, and the results provide insight and data for computing the flow between the parrallel disks mentioned. Applicability of the results to the disk friction drag of centrifugal pump impeller shrouds is claimed.
Download or read book Instability and Transition in Rotating Disk Flow written by and published by . This book was released on 1981 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of the Rotating disk Boundary layer Flow written by and published by . This book was released on 2014 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1991 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
