Roughness scale dependence of the relationship between tracer longitudinal dispersion and Peclet number in variable-aperture fractures

2018 ◽  
Vol 32 (10) ◽  
pp. 1461-1475 ◽  
Author(s):  
Zhi Dou ◽  
Zhifang Zhou ◽  
Jinguo Wang ◽  
Yong Huang
Keyword(s):  
Peclet Number ◽  
Scale Dependence ◽  
Longitudinal Dispersion ◽  
Péclet Number ◽  
Variable Aperture ◽  
The Relationship

Effect of Peclet Number in Thermo-Mechanical Cracking Due to High-Speed Friction Load

1988 ◽  
Vol 110 (2) ◽  
pp. 217-221 ◽  
Author(s):  
F. D. Ju ◽  
J. C. Liu
Keyword(s):  
Tensile Stress ◽  
Peclet Number ◽  
High Speed ◽  
Property Values ◽  
Critical Depth ◽  
Two Dimensional ◽  
Péclet Number ◽  
Parametric Effects ◽  
The Relationship ◽  
Thermal Tensile Stress

The present paper discussed the critical depth, i.e., the depth at which the thermal tensile stress reaches a maximum, caused by the frictional excitation of a fast moving asperity. In the study, the critical depth was computed directly by maximizing the thermal tensile stress with respect to positions under the asperity inside the material. The relationship between critical depth and Peclet number for all materials in the two-dimensional formulation may be simplified to satisfy the exponential form R(ηcr)2.275=20.4368. Stellite III was chosen as the indicator material. Other parametric effects including mechanical properties and thermal properties were tested with materials having diverse property values. These tests confirmed that for the two-dimensional formulation, the Peclet number is the only one which dominates the critical depth.

scholarly journals Temporal Mixing Behavior of Conservative Solute Transport through 2D Self-Affine Fractures

Processes ◽  
2018 ◽  
Vol 6 (9) ◽  
pp. 158 ◽  
Author(s):  
Zhi Dou ◽  
Brent Sleep ◽  
Pulin Mondal ◽  
Qiaona Guo ◽  
Jingou Wang ◽  
...  
Keyword(s):  
Peclet Number ◽  
Hurst Exponent ◽  
Temporal Evolution ◽  
Dominant Role ◽  
Scalar Dissipation ◽  
Péclet Number ◽  
Mixing Behavior ◽  
Power Law Function ◽  
Variable Aperture ◽  
Aperture Distribution

In this work, the influence of the Hurst exponent and Peclet number (Pe) on the temporal mixing behavior of a conservative solute in the self-affine fractures with variable-aperture fracture and constant-aperture distributions were investigated. The mixing was quantified by the scalar dissipation rate (SDR) in fractures. The investigation shows that the variable-aperture distribution leads to local fluctuation of the temporal evolution of the SDR, whereas the temporal evolution of the SDR in the constant-aperture fractures is smoothly decreasing as a power-law function of time. The Peclet number plays a dominant role in the temporal evolution of mixing in both variable-aperture and constant-aperture fractures. In the constant-aperture fracture, the influence of Hurst exponent on the temporal evolution of the SDR becomes negligible when the Peclet number is relatively small. The longitudinal SDR can be related to the global SDR in the constant-aperture fracture when the Peclet number is relatively small. As the Peclet number increases the longitudinal SDR overpredicts the global SDR. In the variable-aperture fractures, predicting the global SDR from the longitudinal SDR is inappropriate due to the non-monotonic increase of the longitudinal concentration second moment, which results in a physically meaningless SDR.

Estimation of capillary reflection coefficients and unique PS products in dog paw

1989 ◽  
Vol 257 (3) ◽  
pp. H1037-H1041 ◽  
Author(s):  
R. K. Reed ◽  
M. I. Townsley ◽  
A. E. Taylor
Keyword(s):  
Total Protein ◽  
Peclet Number ◽  
Reflection Coefficients ◽  
Plasma Protein Concentration ◽  
Linear Portion ◽  
Péclet Number ◽  
Capillary Membrane ◽  
Permeability Surface ◽  
The Relationship ◽  
Ig G

Lymphatic protein flux (Js) obtained in canine hindpaws at low lymph flows were used to determine the capillary osmotic reflection coefficients (sigma d) and unique permeability surface area (PS) products for total proteins, albumin, immunoglobulin (Ig)G, and IgM. This new analysis is based on the phenomenon that when maximal diffusion occurs across the capillary membrane, the Peclet number [x = Jv(1 - sigma d)/PS] attains a unique value defined only by sigma d. The diffusive flux is maximal when the relationship between protein flux and transcapillary fluid flux (Jv) changes from a curvilinear to a linear relationship. The slope of the linear portion of this protein flux relationship was used to determine sigma d as (1 - sigma d) = delta Js/(delta JvCp), where Cp is the plasma protein concentration. With the use of sigma d, the Jv at which the maximal diffusion occurred, and the corresponding Peclet number, a unique value is obtained for the PS product. Experiments performed using lymph from canine hindpaws (n = 6) yielded sigma d's (mean +/- SD) of 0.91 +/- 0.03, 0.83 +/- 0.11, 0.96 +/- 0.03, and virtually 1 for total protein, albumin, IgG, and IgM, respectively. The corresponding PS products for total protein, albumin, and IgG were 25.0 +/- 13.2, 28.4 +/- 6.6, and 14.0 +/- 7.9 microliters.min-1.100 g-1, respectively; PS for IgM was almost zero.(ABSTRACT TRUNCATED AT 250 WORDS)

Approximate analysis of the containment of contaminated sites prior to remediation

2000 ◽  
Vol 42 (1-2) ◽  
pp. 319-324 ◽  
Author(s):  
H. Rubin ◽  
A. Rabideau
Keyword(s):  
Steady State ◽  
Peclet Number ◽  
Dimensionless Parameter ◽  
Contaminated Sites ◽  
Unsteady State ◽  
Péclet Number ◽  
Vertical Barrier ◽  
Time Period ◽  
Barrier Performance ◽  
Vertical Barriers

This study presents an approximate analytical model, which can be useful for the prediction and requirement of vertical barrier efficiencies. A previous study by the authors has indicated that a single dimensionless parameter determines the performance of a vertical barrier. This parameter is termed the barrier Peclet number. The evaluation of barrier performance concerns operation under steady state conditions, as well as estimates of unsteady state conditions and calculation of the time period requires arriving at steady state conditions. This study refers to high values of the barrier Peclet number. The modeling approach refers to the development of several types of boundary layers. Comparisons were made between simulation results of the present study and some analytical and numerical results. These comparisons indicate that the models developed in this study could be useful in the design and prediction of the performance of vertical barriers operating under conditions of high values of the barrier Peclet number.

Convective diffusion toward the sphere in laminar flow around the sphere

1979 ◽  
Vol 44 (4) ◽  
pp. 1218-1238
Author(s):  
Arnošt Kimla ◽  
Jiří Míčka
Keyword(s):  
Laminar Flow ◽  
Velocity Profile ◽  
Peclet Number ◽  
Convective Diffusion ◽  
Péclet Number ◽  
Stability Of The Solution

The problem of convective diffusion toward the sphere in laminar flow around the sphere is solved by combination of the analytical and net methods for the region of Peclet number λ ≥ 1. The problem was also studied for very small values λ. Stability of the solution has been proved in relation to changes of the velocity profile.

Convective diffusion to a slowly rotating spherical electrode; Basic model for Re → O, Pe → ∞

1983 ◽  
Vol 48 (6) ◽  
pp. 1571-1578 ◽  
Author(s):  
Ondřej Wein
Keyword(s):  
Boundary Layer ◽  
Flow Regime ◽  
Peclet Number ◽  
Convective Diffusion ◽  
Creeping Flow ◽  
Péclet Number ◽  
Spherical Electrode ◽  
Basic Model ◽  
Boundary Layer Solution ◽  
Layer Solution

Theory has been formulated of a convective rotating spherical electrode in the creeping flow regime (Re → 0). The currently available boundary layer solution for Pe → ∞ has been confronted with an improved similarity description applicable in the whole range of the Peclet number.

Modeling temperature rise in multi-track reciprocating frictional sliding

2021 ◽  
pp. 135065012098823
Author(s):  
Thierry A Blanchet
Keyword(s):  
Temperature Rise ◽  
Peclet Number ◽  
Maximum Temperature ◽  
Uniform Heat Flux ◽  
Heat Accumulation ◽  
Stroke Length ◽  
Péclet Number ◽  
Maximum Temperature Rise ◽  
Rectangular Patch ◽  
Accumulation Effect

As in various manufacturing processes, in sliding tests with scanning motions to extend the sliding distance over fresh countersurface, temperature rise during any pass is bolstered by heating during prior passes over neighboring tracks, providing a “heat accumulation effect” with persisting temperature rises contributing to an overall temperature rise of the current pass. Conduction modeling is developed for surface temperature rise as a function of numerous inputs: power and size of heat source; speed and stroke length, and track increment of scanning motion; and countersurface thermal properties. Analysis focused on mid-stroke location for passes of a square uniform heat flux sufficiently far into the rectangular patch being scanned from the first pass at its edge that steady heat accumulation effect response is adopted, focusing on maximum temperature rise experienced across the pass' track. The model is non-dimensionalized to broaden the applicability of the output of its runs. Focusing on practical “high” scanning speeds, represented non-dimensionally by Peclet number (in excess of 40), applicability is further broadened by multiplying non-dimensional maximum temperature rise by the square root of Peclet number as model output. Additionally, investigating model runs at various non-dimensional speed (Peclet number) and reciprocation period values, it appears these do not act as independent inputs, but instead with their product (non-dimensional stroke length) as a single independent input. Modified maximum temperature rise output appears to be a function of only two inputs, increasing with decreasing non-dimensional values of stroke length and scanning increment, with outputs of models runs summarized compactly in a simple chart.

Sign in / Sign up

Export Citation Format

Share Document