Modeling of water rising in hydraulically coupled cylindrical capillaries of different radii

Abstract

Introduction. Vertical upward flow of water in the plant xylem occurs under the action of the water surface tension in the capillary menisci. In some papers, it is shown that the distribution of water in the inclined capillary systems is subject to the general rule: movement of water reaches a maximum in the branches of a lower level. In this case, the water height in a vertical capillary is proportional to the number of lateral branches in the capillary system. A set of issues remains open, among them: the role of bordered pores providing a hydraulic connection between vessels; effect of pore sizes and parameters of hydraulically coupled vessels on the water rise in them. 

Materials and Methods. A model of the system consisting of two vertical capillaries of different radii is considered. They touch one another by side walls and are immersed in water. Calculations describing the relationships of the elements of the given system are carried out.

Research Results. It is established that the height of water in hydraulically coupled capillaries is generally different.

Discussion and Conclusions. The dependence is shown: the smaller the difference in level between pores and the closer the pore is to the water surface, the higher the water in the capillaries rises.