Constant Pressure Laminar, Transitional and Turbulent Flows—An Approximate Unified Treatment

2002 ◽  
Vol 124 (3) ◽  
pp. 806-808
Author(s):  
J. Dey
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Turbulent Flows ◽  
Constant Pressure ◽  
Transitional Flow ◽  
Two Dimensional ◽  
Boundary Layer Flows

A nondimensional number that is constant in two-dimensional, incompressible and constant pressure laminar and fully turbulent boundary layer flows has been proposed. An extension of this to constant pressure transitional flow is discussed.

An Investigation of two Turbulent Flows over Smooth and Rough Surfaces

1974 ◽  
Vol 16 (2) ◽  
pp. 71-78 ◽  
Author(s):  
W. K. Allan ◽  
V. Sharma
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Surface Roughness ◽  
Turbulent Boundary Layer ◽  
Turbulent Flows ◽  
Smooth Surface ◽  
Two Dimensional ◽  
Mean Velocity ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow

Experimental data for two-dimensional, low-speed, turbulent boundary layer flow has been used to verify the description of mean-velocity distributions proposed by Allan and to re-evaluate the entrainment function. The independence of pressure gradient and surface roughness as regards their effects on velocity profiles has been demonstrated. Boundary layer predictions agree with experimental data for a smooth surface, but further investigation is required for flow over a rough surface.

Particle Concentration Variation for Inflow Profiles in High Reynolds Number Turbulent Boundary Layer

2020 ◽  
Author(s):  
Mustafa M. Rahman ◽  
Ravi Samtaney
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Turbulent Flows ◽  
Particle Concentration ◽  
Solid Particles ◽  
Scale Model ◽  
Normal Velocity ◽  
Boundary Layer Flows ◽  
Ground Field ◽  
High Reynolds

Abstract Large-eddy simulations (LES) of incompressible turbulent boundary-layer flows can simulate a fundamental unsteady turbulent flow, including time-variant streamwise and wall-normal velocity as well as the near-wall locations of significant turbulence intensities. A typical illustration of turbulent flows with such high Reynolds numbers can be roughly approximated to atmospheric boundary-layer flows. To bypass the demanding mesh criteria of near-ground field and direct numerical simulations, we adopt a virtual-wall model with a stretched-vortex subgrid-scale model. We simulate the dynamics of solid particles in this wall-modeled LES approach toward incompressible flow. The particles considered are both charged and uncharged, and have a fixed concentration profile with no fluctuations at the inflow. An extended streamwise simulation domain is implemented as an alternative to rerunning the simulation with a turbulent inflow profile from the simulation of the previous downstream profile. By extending the streamwise domain, the fluctuation dynamics of the particles reach a steady state far downstream from the inflow. The streamwise and altitude variation of the particle parameters are compared for various particle-concentration inflow profiles. Furthermore, an estimate of the streamwise variation of parameters is also observed. This study is the first step towards enhancing our understanding of the particle dynamics in turbulent flows.

Axisymmetric turbulent boundary layer along a circular cylinder at constant pressure

1976 ◽  
Vol 74 (1) ◽  
pp. 113-128 ◽  
Author(s):  
Noor Afzal ◽  
R. Narasimha
Keyword(s):  
Boundary Layer ◽  
Circular Cylinder ◽  
Turbulent Boundary Layer ◽  
Constant Pressure ◽  
Axisymmetric Flow ◽  
Universal Constant ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Flow Experiment ◽  
Two Dimensional Flow

A constant-pressure axisymmetric turbulent boundary layer along a circular cylinder of radiusais studied at large values of the frictional Reynolds numbera+(based upona) with the boundary-layer thickness δ of ordera. Using the equations of mean motion and the method of matched asymptotic expansions, it is shown that the flow can be described by the same two limit processes (inner and outer) as are used in two-dimensional flow. The condition that the two expansions match requires the existence, at the lowest order, of a log region in the usual two-dimensional co-ordinates (u+,y+). Examination of available experimental data shows that substantial log regions do in fact exist but that the intercept is possibly not a universal constant. Similarly, the solution in the outer layer leads to a defect law of the same form as in two-dimensional flow; experiment shows that the intercept in the defect law depends on δ/a. It is concluded that, except in those extreme situations wherea+is small (in which case the boundary layer may not anyway be in a fully developed turbulent state), the simplest analysis of axisymmetric flow will be to use the two-dimensional laws with parameters that now depend ona+or δ/aas appropriate.

COMPUTATION OF TWO-DIMENSIONAL INCOMPRESSIBLE TURBULENT BOUNDARY LAYER FLOWS WITH EQUILIBRIUM AND NONEQUILIBRIUM TURBULENCE MODELS

1994 ◽  
Vol 05 (02) ◽  
pp. 207-210
Author(s):  
Daniel Wong ◽  
Salahuddin Ahmed
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Turbulence Models ◽  
Two Dimensional ◽  
Reynolds Stresses ◽  
Mean Flow ◽  
Boundary Layer Flows ◽  
Boundary Layer Equations ◽  
Viscosity Models ◽  
Incompressible Turbulent Boundary Layer

Two-dimensional incompressible turbulent boundary layer flows over a flat plate were predicted using turbulent boundary layer equations. Reynolds stresses were calculated using Cebeci-Smith, Baldwin-Lomax, and Johnson-King eddy viscosity models. Computational results of mean-flow properties based on Cebeci-Smith model and Baldwin-Lomax model are in excellent agreement with experimental data, and, those based on Johnson-King model are not as accurate as the other two models.

Sign in / Sign up

Export Citation Format

Share Document