Direct Measurement of Wall Shear Stress With Mass Transfer in a Low Speed Boundary Layer

1977 ◽  
Vol 99 (3) ◽  
pp. 580-584 ◽  
Author(s):  
K. Depooter ◽  
E. Brundrett ◽  
A. B. Strong
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Shear Stress ◽  
Porous Plate ◽  
Feedback System ◽  
Direct Measurements ◽  
Porous Element ◽  
Floating Element ◽  
Asymptotic Suction ◽  
Suction And Blowing

A porous plate floating element is used to obtain direct measurements of shear stress in a transpired zero pressure gradient boundary layer from laminar asymptotic suction to blow-off. The thrust balance incorporates a feedback system which provides self centering of the porous element from zero shear stress up to the maximum encountered. Shear stress data obtained for suction and blowing conditions agree well with previously determined indirect data. The floating element data are well correlated by two equations, one for the suction mode, and one for the blowing mode, via simple modifications of an existing correlation.

Heat and Mass Transfer in an Incompressible Turbulent Boundary Layer

1972 ◽  
Vol 94 (1) ◽  
pp. 23-28 ◽  
Author(s):  
E. Brundrett ◽  
W. B. Nicoll ◽  
A. B. Strong
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Mass Transfer ◽  
Porous Plate ◽  
Mixing Length ◽  
Two Dimensional ◽  
Transfer Data ◽  
Incompressible Turbulent Boundary Layer ◽  
Wide Range ◽  
Incompressible Boundary

The van Driest damped mixing length has been extended to account for the effects of mass transfer through a porous plate into a turbulent, two-dimensional incompressible boundary layer. The present mixing length is continuous from the wall through to the inner-law region of the flow, and although empirical, has been shown to predict wall shear stress and heat transfer data for a wide range of blowing rates.

Mass transfer into boundary layers for power law fluids

1979 ◽  
Vol 365 (1722) ◽  
pp. 313-326 ◽  
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Shear Stress ◽  
Boundary Value Problem ◽  
Wall Friction ◽  
Point Boundary ◽  
Boundary Layer Equations ◽  
Mass Injection ◽  
Power Law Fluids ◽  
Similarity Preserving

The boundary layer equations for the class of non-Newtonian fluids having the shear stress proportional to a power of the strain rate are considered under conditions of similarity-preserving mass transfer at the wall. The adoption of Crocco variables results in a nonlinear, two point boundary value problem for which existence, uniqueness and analyticity are established. In the case of mass injection particular attention is paid to boundary conditions corresponding to the vanishing of the wall friction and values for the (possibly non-existent) critical injection rates are exhibited.

scholarly journals Lagrangian wall shear stress structures and near-wall transport in high-Schmidt-number aneurysmal flows

2016 ◽  
Vol 790 ◽  
pp. 158-172 ◽  
Author(s):  
Amirhossein Arzani ◽  
Alberto M. Gambaruto ◽  
Guoning Chen ◽  
Shawn C. Shadden
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Shear Stress ◽  
Vector Field ◽  
Wall Shear Stress ◽  
Residence Time ◽  
Vessel Wall ◽  
Schmidt Number ◽  
High Schmidt Number ◽  
Near Wall

The wall shear stress (WSS) vector field provides a signature for near-wall convective transport, and can be scaled to obtain a first-order approximation of the near-wall fluid velocity. The near-wall flow field governs mass transfer problems in convection-dominated open flows with high Schmidt number, in which case a flux at the wall will lead to a thin concentration boundary layer. Such near-wall transport is of particular interest in cardiovascular flows whereby haemodynamics can initiate and progress biological events at the vessel wall. In this study we consider mass transfer processes in pulsatile blood flow of abdominal aortic aneurysms resulting from complex WSS patterns. Specifically, the Lagrangian surface transport of a species released at the vessel wall was advected in forward and backward time based on the near-wall velocity field. Exposure time and residence time measures were defined to quantify accumulation of trajectories, as well as the time required to escape the near-wall domain. The effect of diffusion and normal velocity was investigated. The trajectories induced by the WSS vector field were observed to form attracting and repelling coherent structures that delineated species distribution inside the boundary layer consistent with exposure and residence time measures. The results indicate that Lagrangian WSS structures can provide a template for near-wall transport.

Direct Force Wall Shear Measurements in Pressure-Driven Three-Dimensional Turbulent Boundary Layers

1982 ◽  
Vol 104 (2) ◽  
pp. 150-155 ◽  
Author(s):  
J. E. McAllister ◽  
F. J. Pierce ◽  
M. H. Tennant
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Three Dimensional ◽  
Turbulent Boundary Layers ◽  
Direct Measurements ◽  
Stress Directions ◽  
Wall Flow ◽  
Wall Shear ◽  
Pressure Driven

Unique, simultaneous direct measurements of the magnitude and direction of the local wall shear stress in a pressure-driven three-dimensional turbulent boundary layer are presented. The flow is also described with an oil streak wall flow pattern, a map of the wall shear stress-wall pressure gradient orientations, a comparison of the wall shear stress directions relative to the directions of the nearest wall velocity as measured with a typical, small boundary layer directionally sensitive claw probe, as well as limiting wall streamline directions from the oil streak patterns, and a comparison of the freestream streamlines and the wall flow streamlines. A review of corrections for direct force sensing shear meters for two-dimensional flows is presented with a brief discussion of their applicability to three-dimensional devices.

scholarly journals Effects of Binary Chemical Reaction and Activation Energy on MHD Boundary Layer Heat and Mass Transfer Flow with Viscous Dissipation and Heat Generation/Absorption

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Kh. Abdul Maleque
Keyword(s):  
Activation Energy ◽  
Boundary Layer ◽  
Mass Transfer ◽  
Differential Equations ◽  
Heat And Mass Transfer ◽  
Viscous Dissipation ◽  
Chemical Reaction ◽  
Heat Generation ◽  
Porous Plate ◽  
Local Similarity

We study an unsteady MHD free convection heat and mass transfer boundary layer incompressible fluid flow past a vertical porous plate in the presence of viscous dissipation, heat generation/absorption, chemical reaction, and Arrhenius activation energy. The plate is moving with uniform velocity. The chemical reaction rate in the function of temperature is also considered. The governing partial differential equations are reduced to ordinary differential equations by introducing local similarity transformation (Maleque (2010)) and then are solved numerically by shooting method using the Nachtsheim-Swigert iteration technique. The results of the numerical solution are then presented graphically as well as the tabular form for difference values of the various parameters.

scholarly journals MHD free convection and mass transfer flow over an infinite vertical porous plate with viscous dissipation

2010 ◽  
Vol 37 (4) ◽  
pp. 263-287 ◽  
Author(s):  
Hemant Poonia ◽  
R.C. Chaudhary
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Viscous Dissipation ◽  
Porous Plate ◽  
Eckert Number ◽  
Convective Boundary ◽  
Electrically Conducting ◽  
Layer Flow ◽  
Transfer Flow ◽  
Infinite Vertical Plate

An unsteady, two-dimensional, hydromagnetic, laminar mixed convective boundary layer flow of an incompressible and electrically-conducting fluid along an infinite vertical plate embedded in the porous medium with heat and mass transfer is analyzed, by taking into account the effect of viscous dissipation. The dimensionless governing equations for this investigation are solved analytically using two-term harmonic and non-harmonic functions. Numerical evaluation of the analytical results is performed and graphical results for velocity, temperature and concentration profiles within the boundary layer are discussed. The results show that increased cooling (Gr > 0) of the plate and the Eckert number leads to a rise in the velocity profile. Also, an increase in Eckert number leads to an increase in the temperature. Effects of Sc on velocity and concentration are discussed and shown graphically.

NUMERICAL AND ANALYTICAL SOLUTIONS FOR NATURAL CONVECTION FLOW WITH THERMAL RADIATION AND MASS TRANSFER PAST A MOVING VERTICAL POROUS PLATE BY DQM AND HAM

2011 ◽  
Vol 08 (03) ◽  
pp. 611-631 ◽  
Author(s):  
P. TALEBIZADEH ◽  
M. A. MOGHIMI ◽  
A. KIMIAEIFAR ◽  
M. AMERI
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Natural Convection ◽  
Thermal Radiation ◽  
Differential Quadrature Method ◽  
Porous Plate ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Homotopy Analysis ◽  
Excellent Method

In this paper, the boundary-layer natural convection flow on a permeable vertical plate with thermal radiation and mass transfer is studied when the plate moves in its own plane. A uniform temperature with uniform species concentration at the plate is affected and the fluid is considered to be a gray, absorbing–emitting. A viscous flow model is presented using boundary-layer theory comprising the momentum, energy, and concentration equations, which is solved analytically by means of an excellent method called homotopy analysis method (HAM). First, a comparison between HAM results and those obtained by means of a higher-order numerical method, namely differential quadrature method (DQM), is done. Close agreement of two sets of results indicates the accuracy of the HAM. The velocity, temperature, and concentration distributions are displayed graphically, and a parametric study is performed in which the effect of various parameters on the skin friction, the local Nusselt number (Nn), and the local Sherwood number (Mu) are investigated.

Sign in / Sign up

Export Citation Format

Share Document