Liquid drops on vertical and inclined surfaces: I. An experimental study of drop geometry

A. I. ElSherbini, A. M. Jacobi

Research output: Contribution to journalArticlepeer-review


Experiments have been conducted to investigate the geometric parameters necessary to describe the shapes of liquid drops on vertical and inclined plane surfaces. Two liquids and eight surfaces have been used to study contact angles, contact lines, profiles, and volumes of drops of different sizes for a range of surface conditions. The results show the contact-angle variation along the circumference of a drop to be best fit by a third-degree polynomial in the azimuthal angle. This contact-angle function is expressed in terms of the maximum and minimum contact angles of the drop, which are determined for various conditions. The maximum contact angle, θmax, is approximately equal to the advancing contact angle, θA, of the liquid on the surface. As the Bond number, Bo, increases from 0 to a maximum, the minimum contact angle, θmin, decreases almost linearly from the advancing to the receding angle. A general relation is found between θminA and Bo for different liquid-surface combinations. The drop contour can be described by an ellipse, with the aspect ratio increasing with Bo. These experimental results are valuable in modeling drop shape, as presented in Part II of this work.

Original languageEnglish (US)
Pages (from-to)556-565
Number of pages10
JournalJournal of Colloid And Interface Science
Issue number2
StatePublished - May 15 2004


  • Contact angle
  • Contact line
  • Drop profile
  • Drop shape

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry


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