Direct Numerical Simulation Of Turbulent Flow Over A Dimpled Flat Plate Using An Immersed Boundary Technique
DOWNLOAD
Download Direct Numerical Simulation Of Turbulent Flow Over A Dimpled Flat Plate Using An Immersed Boundary Technique PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get Direct Numerical Simulation Of Turbulent Flow Over A Dimpled Flat Plate Using An Immersed Boundary Technique book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages. If the content not found or just blank you must refresh this page
Direct Numerical Simulation Of Turbulent Flow Over A Dimpled Flat Plate Using An Immersed Boundary Technique
DOWNLOAD
Author : Jeremiah J. Gutierrez-Jensen
language : en
Publisher:
Release Date : 2011
Direct Numerical Simulation Of Turbulent Flow Over A Dimpled Flat Plate Using An Immersed Boundary Technique written by Jeremiah J. Gutierrez-Jensen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Computational fluid dynamics categories.
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.
Simulation Of The Flow Over A Flat Dimpled Plate
DOWNLOAD
Author : Jeffrey Michael Mode
language : en
Publisher:
Release Date : 2010
Simulation Of The Flow Over A Flat Dimpled Plate written by Jeffrey Michael Mode and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Boundary layer control categories.
Passive flow control achieved by surface dimpling can be an effective strategy for reducing drag around bluff bodies - an example of substantial popular interest being the flow around a golf ball. While the general effect of dimples causing a delay of boundary layer separation is well known, the mechanisms contributing to this phenomena are subtle and not thoroughly understood. Numerical models offer a powerful approach for studying drag reduction, however simulation strategies are challenged by complex geometries, and in applications the introduction of ad hoc turbulence models which introduce additional uncertainty. These and other factors provide much of the motivation for the current study, which focused on the numerical simulations of the flow over a simplified configuration consisting of a dimpled flat plate. The principal goals of the work are to understand the performance of the numerical methodology, and gain insight into the underlying physics of the flow. Direct numerical simulation of the incompressible Navier-Stokes equations using a fractional step method was employed, with the dimpled flat plate represented using an immersed boundary method. The dimple geometry utilizes a fixed dimple aspect ratio, with dimples arranged in a single spanwise row. The grid sizes considered ranged from approximately 3 to 99 million grid points. Reynolds numbers of 3000 and 4000 based on the inlet laminar boundary layer thickness were simulated. A turbulent boundary layer was induced downstream of the dimples for Reynolds numbers which did not transition for the flow over an undimpled flat plate. First and second order statistics of the boundary layer that develops agree reasonably well with those for turbulent channel flow and flat plate boundary layers in the sublayer and buffer layers, but differ in the outer layer. Inspection of flow visualizations suggest that early transition is promoted by thinning of the boundary layer, initiation of shear layer instabilities over the dimples, flow separation and reattachment, and tripping of the boundary layer at the trailing edge of the dimples.
Turbulence Over A Compliant Surface
DOWNLOAD
Author : Sheng Xu
language : en
Publisher:
Release Date : 2002
Turbulence Over A Compliant Surface written by Sheng Xu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with categories.
Direct Numerical Simulation Of Turbulent Flow Over A Backward Facing Step
DOWNLOAD
Author : Stanford University. Thermosciences Division. Thermosciences Division
language : en
Publisher:
Release Date : 1994
Direct Numerical Simulation Of Turbulent Flow Over A Backward Facing Step written by Stanford University. Thermosciences Division. Thermosciences Division and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1994 with Fluid dynamics categories.
Direct Numerical Simulation Of Turbulent Flow Over A Backward Facing Step
DOWNLOAD
Author : Michal Andrzej Kopera
language : en
Publisher:
Release Date : 2011
Direct Numerical Simulation Of Turbulent Flow Over A Backward Facing Step written by Michal Andrzej Kopera and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
A three-dimensional, turbulent flow in a channel with a sudden expansion was studied by direct numerical simulation of the incompressible Navier-Stokes equations. The objective of this study was to provide statistical data of backwardfacing step flow for turbulence modelling. Additionally, analysis of the statistical and dynamical properties of the flow is performed. The Reynolds number of the main simulation was Reh = 9000, based on the step height and mean inlet velocity, with the expansion ratio ER = 2:0. The discretisation is performed using the spectral/hp element method with stiffly-stable velocity correction scheme for time integration. The inlet boundary condition is a fully turbulent velocity and pressure field regenerated from a plane downstream of the inlet. A constant flowrate was ensured by applying Stokes flow correction in the inlet regeneration area. Time and spanwise averaged results revealed, apart from the primary recirculation bubble, secondary and tertiary corner eddies. Streamlines show an additional small eddy at the downstream tip of the secondary corner eddy, with the same circulation direction as the secondary vortex. The analysis of the 3D, timeonly average shows the wavy spanwise structure of both primary and secondary recirculation bubble, that results in spanwise variations of the mean reattachment location. The visualisation of spanwise averaged pressure uctuations and streamwise velocity showed that the interaction of vortices with the recirculation bubble is responsible for the apping of the reattachment position. The characteristic frequency St = 0:078 was found. The analysis of small-scale energy transfer was performed to reveal large backscatter regions in strong Reynolds stress areas in the mixing layer. High correlation of small-scale transfer with non-linear interaction of large-scale velocity and small-scale vorticity was found. The data of the flow fields was archived. It contains the averages for velocities, pressure and Reynolds stress tensor, as well as 3D instantaneous pressure and velocity history.
Direct Numerical Simulation Of Turbulence With Scalar Transfer Around Complex Geometries Using The Immersed Boundary Method And Fully Conservative Higher Order Finite Difference Schemes
DOWNLOAD
Author : Kouji Nagata
language : en
Publisher:
Release Date : 2010
Direct Numerical Simulation Of Turbulence With Scalar Transfer Around Complex Geometries Using The Immersed Boundary Method And Fully Conservative Higher Order Finite Difference Schemes written by Kouji Nagata and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Computers categories.
Direct Numerical Simulation of Turbulence with Scalar Transfer around Complex Geometries Using the Immersed Boundary Method and Fully Conservative Higher-Order Finite-Difference Schemes.
Direct Numerical Simulation Of Laminar And Turbulent Flow In A Channel With Complex Time Dependent Wall Geometries
DOWNLOAD
Author : Henry Andrew Carlson
language : en
Publisher:
Release Date : 1995
Direct Numerical Simulation Of Laminar And Turbulent Flow In A Channel With Complex Time Dependent Wall Geometries written by Henry Andrew Carlson and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1995 with categories.
Direct Numerical Simulations Of Compressible Turbulent Boundary Layers Using Hybrid Methods
DOWNLOAD
Author : Debra J. Olejniczak
language : en
Publisher:
Release Date : 1998
Direct Numerical Simulations Of Compressible Turbulent Boundary Layers Using Hybrid Methods written by Debra J. Olejniczak and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with categories.
Direct Numerical Simulations Of Boundary Forced Turbulent Flow In A Non Rotating And A Rotating System
DOWNLOAD
Author : Guang Yang
language : en
Publisher:
Release Date : 1992
Direct Numerical Simulations Of Boundary Forced Turbulent Flow In A Non Rotating And A Rotating System written by Guang Yang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1992 with categories.
Analysis Of Weakly Compressible Turbulence Using Symmetry Methods And Direct Numerical Simulation
DOWNLOAD
Author : Raphael Gotthard Harald Arlitt
language : en
Publisher: Cuvillier Verlag
Release Date : 2005
Analysis Of Weakly Compressible Turbulence Using Symmetry Methods And Direct Numerical Simulation written by Raphael Gotthard Harald Arlitt and has been published by Cuvillier Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with categories.
