On surface renewal and sea slicks

2006 ◽  
pp. 65-74 ◽  
Author(s):  
Kristian B. Dysthe
Keyword(s):  
Surface Renewal

Analyzing the Influence of Surface Renewal on Diffusive Mass Transport in Vented Single-Screw Extruders

2017 ◽  
Vol 32 (3) ◽  
pp. 387-393 ◽  
Author(s):  
C. Marschik ◽  
B. Löw-Baselli ◽  
Jürgen Miethlinger
Keyword(s):  
Mass Transport ◽  
Surface Renewal ◽  
Single Screw ◽  
Single Screw Extruders ◽  
Screw Extruders

Sensible heat flux estimates using surface renewal analysis

2009 ◽  
Vol 149 (9) ◽  
pp. 1397-1402 ◽  
Author(s):  
F. Castellví ◽  
R.L. Snyder
Keyword(s):  
Heat Flux ◽  
Sensible Heat Flux ◽  
Sensible Heat ◽  
Surface Renewal

scholarly journals Surface Renewal as a Significant Mechanism for Dust Emission

2016 ◽  
Author(s):  
Jie Zhang ◽  
Zhenjiao Teng ◽  
Ning Huang ◽  
Lei Guo ◽  
Yaping Shao
Keyword(s):  
Wind Tunnel ◽  
Emission Rate ◽  
Dust Emission ◽  
Limit Surface ◽  
Soil Dust ◽  
Flow Conditions ◽  
Wind Tunnel Experiments ◽  
Surface Renewal ◽  
Surface Particle ◽  
Significant Mechanism

Abstract. Wind-tunnel experiments of dust emissions from different soil surfaces are carried out to better understand dust emission mechanisms. The effects of surface renewal on aerodynamic entrainment and saltation bombardment are analysed in detail, and the measurements are used to test published dust models. It is found that flow conditions, surface particle motions (saltation and creep), soil dust content and ground obstacles all strongly affect dust emission, causing dust emission rate to vary over orders of magnitude. Aerodynamic entrainment is highly effective, if dust supply is unlimited, as in the first 2–3 minutes of our wind-tunnel runs. While aerodynamic entrainment is suppressed by dust supply limit, surface renewal through the motion of surface particles is found to be an effective pathway to remove the supply limit. Surface renewal is also found to be important to the efficiency of saltation bombardment. We demonstrate that surface renewal is a significant mechanism affecting dust emission and recommend that this mechanism be included in future dust models.

scholarly journals A frequency quantum interpretation of the surface renewal model of mass transfer

2017 ◽  
Vol 4 (7) ◽  
pp. 170103 ◽  
Author(s):  
Chanchal Mondal ◽  
Siddharth G. Chatterjee
Keyword(s):  
Mass Transfer ◽  
Steady State ◽  
Frequency Distribution ◽  
Age Distribution ◽  
Gas Absorption ◽  
Bulk Liquid ◽  
Gas Transfer ◽  
Transfer Resistance ◽  
Surface Renewal ◽  
Two Parameter

The surface of a turbulent liquid is visualized as consisting of a large number of chaotic eddies or liquid elements. Assuming that surface elements of a particular age have renewal frequencies that are integral multiples of a fundamental frequency quantum, and further assuming that the renewal frequency distribution is of the Boltzmann type, performing a population balance for these elements leads to the Danckwerts surface age distribution. The basic quantum is what has been traditionally called the rate of surface renewal. The Higbie surface age distribution follows if the renewal frequency distribution of such elements is assumed to be continuous. Four age distributions, which reflect different start-up conditions of the absorption process, are then used to analyse transient physical gas absorption into a large volume of liquid, assuming negligible gas-side mass-transfer resistance. The first two are different versions of the Danckwerts model, the third one is based on the uniform and Higbie distributions, while the fourth one is a mixed distribution. For the four cases, theoretical expressions are derived for the rates of gas absorption and dissolved-gas transfer to the bulk liquid. Under transient conditions, these two rates are not equal and have an inverse relationship. However, with the progress of absorption towards steady state, they approach one another. Assuming steady-state conditions, the conventional one-parameter Danckwerts age distribution is generalized to a two-parameter age distribution. Like the two-parameter logarithmic normal distribution, this distribution can also capture the bell-shaped nature of the distribution of the ages of surface elements observed experimentally in air–sea gas and heat exchange. Estimates of the liquid-side mass-transfer coefficient made using these two distributions for the absorption of hydrogen and oxygen in water are very close to one another and are comparable to experimental values reported in the literature.

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