Details
| Original language | English |
|---|---|
| Pages (from-to) | 11-16 |
| Number of pages | 6 |
| Journal | International agrophysics |
| Volume | 18 |
| Issue number | 1 |
| Publication status | Published - 2004 |
Abstract
Earlier results had shown that the contracting force of water films between parallel solid surfaces increased when they were deformed to give longer menisci by subdividing the water volume. Since deformations of this kind will occur regularly when soils are tilled or wheeled with machinery the question was raised how such events would change soil capillary properties. Circular capillaries with a concave inner surface were compared to the ones with a convex inner surface. They were formed by the fixing of either three or four rods with circular diameter together. Perimeters and cross-sectional areas were calculated and the height of capillary rise was measured by two independent methods. For comparison, the results of wetting angles were used. They were calculated from an average inner diameter of the capillaries and separately measured using the height of menisci. The present results showed that in the convex capillaries, higher angles were calculated in comparison to those independently measured at the outsides of rods and tubes. The angles calculated from the capillary height measured in the circular capillaries were smaller than those measured at the outside of the tubes. It was concluded that the wetting angles measured directly with an optical equipment were affected by the solid phase geometry. The above result emphasized that contact angles resulted from a combination of several distinct factors. The curvature of the contact line is one of them.
Keywords
- Capillary cross section, Capillary rise, Wetting angles
ASJC Scopus subject areas
- Environmental Science(all)
- Water Science and Technology
- Agricultural and Biological Sciences(all)
- General Agricultural and Biological Sciences
- Agricultural and Biological Sciences(all)
- Soil Science
- Chemical Engineering(all)
- Fluid Flow and Transfer Processes
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In: International agrophysics, Vol. 18, No. 1, 2004, p. 11-16.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Influence of the cross-section shape in the capillaries on the wetting properties demonstrated by the calculated wetting angles
AU - Hartge, K. H.
AU - Bachmann, J.
AU - Woche, S. K.
N1 - Copyright: Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2004
Y1 - 2004
N2 - Earlier results had shown that the contracting force of water films between parallel solid surfaces increased when they were deformed to give longer menisci by subdividing the water volume. Since deformations of this kind will occur regularly when soils are tilled or wheeled with machinery the question was raised how such events would change soil capillary properties. Circular capillaries with a concave inner surface were compared to the ones with a convex inner surface. They were formed by the fixing of either three or four rods with circular diameter together. Perimeters and cross-sectional areas were calculated and the height of capillary rise was measured by two independent methods. For comparison, the results of wetting angles were used. They were calculated from an average inner diameter of the capillaries and separately measured using the height of menisci. The present results showed that in the convex capillaries, higher angles were calculated in comparison to those independently measured at the outsides of rods and tubes. The angles calculated from the capillary height measured in the circular capillaries were smaller than those measured at the outside of the tubes. It was concluded that the wetting angles measured directly with an optical equipment were affected by the solid phase geometry. The above result emphasized that contact angles resulted from a combination of several distinct factors. The curvature of the contact line is one of them.
AB - Earlier results had shown that the contracting force of water films between parallel solid surfaces increased when they were deformed to give longer menisci by subdividing the water volume. Since deformations of this kind will occur regularly when soils are tilled or wheeled with machinery the question was raised how such events would change soil capillary properties. Circular capillaries with a concave inner surface were compared to the ones with a convex inner surface. They were formed by the fixing of either three or four rods with circular diameter together. Perimeters and cross-sectional areas were calculated and the height of capillary rise was measured by two independent methods. For comparison, the results of wetting angles were used. They were calculated from an average inner diameter of the capillaries and separately measured using the height of menisci. The present results showed that in the convex capillaries, higher angles were calculated in comparison to those independently measured at the outsides of rods and tubes. The angles calculated from the capillary height measured in the circular capillaries were smaller than those measured at the outside of the tubes. It was concluded that the wetting angles measured directly with an optical equipment were affected by the solid phase geometry. The above result emphasized that contact angles resulted from a combination of several distinct factors. The curvature of the contact line is one of them.
KW - Capillary cross section
KW - Capillary rise
KW - Wetting angles
UR - http://www.scopus.com/inward/record.url?scp=2642586425&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:2642586425
VL - 18
SP - 11
EP - 16
JO - International agrophysics
JF - International agrophysics
SN - 0236-8722
IS - 1
ER -