Download or read book Particle Entrainment Under Non uniform Flow Created by an Impinging Jet written by Robert B. Haehnel and published by . This book was released on 2011 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics of Particle Entrainment Under the Influence of an Impinging Jet written by and published by . This book was released on 2008 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the laboratory we used an idealized rotorwash flow - an axisymmetric jet impinges normally on a packed bed of cohesionless particles - and measured the spatially varying flow field and entrainment flux under an axisymmetric jet over a range of jet exit velocities and bed materials. We found that the erosion of the bed is driven by turbulent surface shear stress, quantified by the turbulent kinetic energy of the flow. This observation differs from uniform flow parallel to the bed wherein the flux of particles being removed from the bed depends linearly on the average surface shear stress of the fluid imposed on the bed. We discuss the implications of these findings for applying a general model for capturing particle entrainment under impinging flows.
Download or read book Theoretical and Experimental Studies of Impinging Uniform Jets written by Cornell Aeronautical Laboratory and published by . This book was released on 1963 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of the Aero space Sciences written by and published by . This book was released on 1962 with total page 1550 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book THEORETICAL AND EXPERIMENTAL STUDIES OF IMPINGING UNIFORM JETS written by and published by . This book was released on 1963 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: A theoretical and experimental study was made to investigate the flow characteristics of circular uniform jets impinging normally on a ground plane in order to further the understanding of the aerodynamic processes associated with ground particle entrainment in the impinging downwash of VTOL aircraft. Particular emphasis was placed on the flow properties in the ground-plane boundary layer where entrainment occurs.
Download or read book Journal of the American Helicopter Society written by American Helicopter Society and published by . This book was released on 1962 with total page 818 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solid particles Deposition Through a Turbulent Impinging Jet Using Lattice Boltzmann Method written by Ali Abdulkadhim and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid particle distribution on an impingement surface has been simulated utilizing a graphical processing unit (GPU). An in-house computational fluid dynamics (CFD) code has been developed to investigate a 3D turbulent impinging jet using the lattice Boltzmann method (LBM) in conjunction with large eddy simulation (LES) and the multiple relaxation time (MRT) models. This work proposed an improvement in the LBM-cellular automata (LBM-CA) probabilistic method. In the current model, the fluid flow utilizes the D3Q19 LBM lattice model, while the particles movement employs the D3Q27 one. The particle numbers are defined at the same regular LBM (fluid) nodes, and the transport of particles from one node to its neighbouring nodes are determined in accordance with the particle bulk density and velocity by considering all the external forces. The previous CA models distribute particles at each time step without considering the local particles number and velocity at each node. The present model overcomes the deficiencies of the previous LBM-CA models and, therefore, can better capture the dynamic interaction between particles and the surrounding turbulent flow field. Despite increasing popularity of the LBM-MRT model in simulating complex multiphase fluid flows, this approach is still expensive in term of memory size and computational time required to perform 3D simulations. To improve the throughput of simulations, a single GeForce GTX TITAN X GPU is used in the present work. The CUDA parallel programming platform and the CuRAND library are utilized to form an efficient LBM-MRT-CA algorithm. The LBM-MRT fluid (i.e. no particles) model results were compared with two benchmark test cases ones. The first case is a turbulent free square jet, and the second one is a circular turbulent impinging jet for L/D=2 at Reynolds number equals to 25,000, where L is the nozzle-to-surface distance and D is the jet diameter. The LBM-CA simulation methodology was first validated against a benchmark test case involving particle deposition on a square cylinder confined in a duct. The flow was unsteady and laminar at Re=200 (Re is the Reynolds number), and simulations were conducted for different Stokes numbers. The GPU code was then used to simulate the particle transport and deposition in a turbulent impinging jet at Re=10,000. The effect of changing Stokes number on the particle deposition profile was studied at different L/D ratios, i.e. L/D=2, 4, and 6. The current model was finally used to simulate the particle impaction pattern from a circular jet for L/D=0.5, where the effect of changing Stokes and Reynolds numbers on the particle transport and deposition was examined. The present LBM-CA solutions agree well with other results available in the open literature. For comparative studies, another in-house serial CPU code was also developed, coupling LBM with the classical Lagrangian particle dispersion model. Agreement between results obtained with LBM-CA and LBM-Lagrangian models and the experimental data for the impinging jet case of L/D=0.5 is generally good, and the present LBM-CA approach on GPU achieves a speedup ratio of about 150 against the serial code running on a single CPU. Another new model was proposed to incorporate the solid particle phase effect (i.e. two-way coupling) on the fluid flow. The LMB-Lagrangian approach was used in this model to track solid particles in the computational domain. The solid particle phase was considered as a porous medium moving in the computational domain. The impact of the porous medium (i.e. the solid particle phase) on the fluid flow characteristics (e.g. fluid velocity) is a function of the particle phase volume fraction and velocity in the LBM. Particle-particle collision (i.e. four-way coupling) was also considered in this model by utilizing the discrete element method (DEM). This approach can numerically capture the multi-particle collision behaviours in dense particle suspension problems. This model data were compared with the numerical study ones for a single bubble injected in a fluidized bed, and the results of the bubble diameters at different injection velocity were in good agreement.
Download or read book An Investigation of Particle Behavior in a Compressible Impinging Jet Flow written by L. Meade and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1976 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Government Research Reports written by and published by . This book was released on 1963 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Flows written by Jean Piquet and published by Springer Science & Business Media. This book was released on 2001-03-26 with total page 778 pages. Available in PDF, EPUB and Kindle. Book excerpt: obtained are still severely limited to low Reynolds numbers (about only one decade better than direct numerical simulations), and the interpretation of such calculations for complex, curved geometries is still unclear. It is evident that a lot of work (and a very significant increase in available computing power) is required before such methods can be adopted in daily's engineering practice. I hope to l"Cport on all these topics in a near future. The book is divided into six chapters, each· chapter in subchapters, sections and subsections. The first part is introduced by Chapter 1 which summarizes the equations of fluid mechanies, it is developed in C~apters 2 to 4 devoted to the construction of turbulence models. What has been called "engineering methods" is considered in Chapter 2 where the Reynolds averaged equations al"C established and the closure problem studied (§1-3). A first detailed study of homogeneous turbulent flows follows (§4). It includes a review of available experimental data and their modeling. The eddy viscosity concept is analyzed in §5 with the l"Csulting ~alar-transport equation models such as the famous K-e model. Reynolds stl"Css models (Chapter 4) require a preliminary consideration of two-point turbulence concepts which are developed in Chapter 3 devoted to homogeneous turbulence. We review the two-point moments of velocity fields and their spectral transforms (§ 1), their general dynamics (§2) with the particular case of homogeneous, isotropie turbulence (§3) whel"C the so-called Kolmogorov's assumptions are discussed at length.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1016 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Government Research Reports written by and published by . This book was released on 1963 with total page 1322 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Trends in Fluid Mechanics Research written by F. G. Zhuang and published by Springer Science & Business Media. This book was released on 2009-04-24 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is the proceedings of the Fifth International Conference on Fluid Mechanics (ICFM-V), the primary forum for the presentation of technological advances and research results in the fields of theoretical, experimental, and computational Fluid Mechanics. Topics include: flow instability and turbulence, aerodynamics and gas dynamics, industrial and environmental fluid mechanics, biofluid mechanics, geophysical fluid mechanics, plasma and magneto-hydrodynamics, and others.
Download or read book Entrainment Processes for a Jet in Cross Flow written by and published by . This book was released on 2020 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: A jet in cross flow (JICF) is examined experimentally by injecting a stream of air into crossing fluid with an aim into quantifying entrainment process and downstream evolution. The behavior of JICF is important to fields ranging from turbine-blade cooling to smokestack pollution and volcanic eruption dynamics. Existing simplified volcanic plume models are tested; most importantly, the near-field contributions of complex interconnected vortex systems, which present significant uncertainties because they assume negligible turbulence. While jets in irrotational cross-flow have been investigated, this analysis has focused on the interaction between a turbulent jet in low and highly turbulent cross-flow created by an active grid. Instantaneous velocity fields were collected over seven planes using particle image velocimetry (PIV). A center-plane (x-y) and six planes parallel to the floor (x-z) highlight the interaction and resulting vortex systems. Various jet-to-cross-flow velocity ratios, Rv, were collected for each plane, which allow for computation of mean statistics and Reynolds stresses. Analysis was focused in five stages: a) identification of differences in the development of the jet across various inflow conditions, b) analysis of the vortex systems through transport and critical points analysis, c) decomposition of the flow structures to identify and remove the highest-order contributions to turbulence kinetic energy and d) extraction of reduced order modeling closure terms and e) optimization of closure terms for the simplified one-dimensional model, Plumeria. These five stages provided a comprehensive description of the role of cross-flow turbulence on the development of JICF. Noteworthy findings include significant changes in wake recovery and the near-wake recirculation region that impacted near-field entrainment; increased entrainment for high cross-flow turbulence after the collapse of the potential core due to increased engulfment and viscous nibbling between turbulent fluids; the presence of shear layer and wake vortices through critical point analysis; and the absence of entrainment and shear layer expansion near the exit. Most importantly, the negligible entrainment near the exit and impact of small scale turbulent features that must be included for any specific model to yield reasonable predictions is highlighted. By laying the foundation for a more nuanced approach to JICF, it is possible to more precisely summarize the complex features observed in this work through simplified descriptions that can be of benefit to both engineering design and geophysical modeling.
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1976 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1983 with total page 1368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
