Author: Anh-Tuan LePublisher:
ISBN:
Category :
Languages : en
Pages : 380
Book Description
A Numerical Study of Three-dimensional Turbulent Boundary Layers
Author: Anh-Tuan LeNumerical Study of a Three-dimensional Turbulent Boundary Layer
Author: Parviz MoinPublisher:
ISBN:
Category : Three-dimensional modeling
Languages : en
Pages : 24
Book Description
Numerical Simulation of a Three-dimensional Turbulent Boundary Layer
Author: Parviz MoinThree-dimensional Turbulent Boundary Layers
Author: O. SendstadPublisher:
ISBN:
Category : Simulation methods
Languages : en
Pages : 130
Book Description
Numerical Study of Three-Dimensional Turbulent Flows
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 72
Book Description
Direct numerical and large-eddy simulations were used to perform numerical experiments' relevant to the cases of interest. We employ a plane-channel geometry and impose mean-flow perturbations by subjecung fully developed 2D Poiseuille flow to irrotational deformations andlor in-plane motion of the channel walls. The former corresponds to outer-layer strains induced in boundary layers by pressure gradients, the latter to sudden variations in the near-wall region, caused by either step changes in the surface conditions or the combination of an outer-layer change and the no-slip boundary condition. This combination allows the physics of a broad class of spatially developing wall shear layers to be duplicated with a temporally evolving channel flow. The temporal computations can be realized much more effectively than can simulations of a spatial boundary layer. providing a much more extensive study for a given cost. As a consequence. we can consider a wide variety of mean-flow perturbations. Moreover, since mean statistics for these flows satisfy a one dimensional unsteady problem that contains the essential features of the spatial flow, they provide an effident means of testing on%point dosure models.
Advances in Three-dimensional Turbulent Boundary Layers with Emphasis on the Wall-layer Regions
Author: Stanford University. Thermosciences Division. Thermosciences DivisionPublisher:
ISBN:
Category :
Languages : en
Pages : 46
Book Description
Numerical Simulation of Unsteady Three-Dimensional Turbulent Structures in Boundary Layer Flows
Author: Nan S. LuiPublisher:
ISBN:
Category :
Languages : en
Pages : 45
Book Description
The capabilities for numerical simulations of the dynamical effects of the underlying structures occurring in turbulent boundary layers have been developed. A mathematically operational model of hairpin vortex, which closely resembles the experimentally observed underlying structure of wall turbulence, has been constructed and the evolution of this incipient hairpin vortex as well as the distortion of a background laminar boundary layer has been successfully simulated. The height of the incipient hairpin vortex is about 1/5 fo the local boundary layer thickness. The calculated results not only exhibit most of the prominent features associated with turbulent spots and turbulent boundary layer flows, but also reveal dynamic processes which have been very difficult to observe in experimental studies, notably, the formation and intensification of another counter rotating hairpin vortex immediately upstream of the incipient hairpin vortex. Keywords: Navier-Stokes equations; Coherent wall structure.
Numerical Study of Some Engineering Turbulence Models for Three-dimensional Boundary-layers
Author: Marco S.G. BetteliniPublisher:
ISBN:
Category :
Languages : en
Pages : 199
Book Description
Three-dimensional, Numerical Study of Boundary-layer Stability
Author: John W. MurdochPublisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 16
Book Description
Three-Dimensional Turbulent Boundary Layer
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 127
Book Description
The near wall mechanics of 3D turbulent boundary layers were studied using direct numerical simulation. A fully developed turbulent channel flow was suddenly subjected to a transverse pressure gradient. An explanation for the reduction in the Reynolds stresses, observed in experiments, was provided in terms of the dynamics of near-wall streamwise vortices in turbulent boundary layers was described. It was shown that the effect of three-dimensionality is to change the trajectory of fluid particles in the vicinity of these vortices, and how this change leads to reductions of turbulence stresses. The proposed mechanisms are consistent with numerous statistical data and correlations which are presented. Turbulence, Boundary layers, Simulation.