IMPROVEMENT OF THE METHODOLOGY FOR DESIGNING SOIL PROTECTION TECHNOLOGIES ON SLOPE AGRICULTURAL LANDSCAPES

Abstract

The main purpose of the work is to clarify the values of soil erosion resistance. In the existing methods for assessing the erosion resistance of soils, the kinetic and potential energy of the water flow is studied. It is believed that the decrease in total energy in the process of flowing along the channel is associated with the work of the water flow in destroying and washing away the soil. However, this does not take into account the energy of capillary waves existing on the water surface during laminar flow. The frequency of the capillary waves is usually such that the waves are not visible to the naked eye and are therefore not taken into account, although their energy is, in order of magnitude, comparable to the energy of the flow. Refinement of the value of erosion resistance is associated with the ability to evaluate and take into account the energy of capillary waves. The work is related to the development of a methodology for accounting and evaluating the contribution of the energy of capillary waves to the total energy of a water microflow, which has a destructive and eroding effect on the soil of a sloping agricultural landscape. The paper developed a mathematical model for estimating the energy of capillary waves, on the basis of which an expression was obtained to determine the ratio of the energy of capillary waves formed on the surface of a water flow to the kinetic energy of the water flow. To experimentally study the process of development of capillary waves on smooth and rough surfaces and determine the operating parameters, an installation was created in the form of a rectangular-section tray with an adjustable inclination angle, adjustable intensity of water supply and replaceable working surfaces. The geometry of the microflow and the shape of its surface were determined from the results of video filming and the readings of the laser rangefinder. In the range of regime parameters studied in this work, the numerical estimation of the dependence of the energy of capillary waves on the kinetic energy of the water flow for the first time revealed a significant (up to 40–60%) contribution of capillary waves formed on the surface of microflows to the total energy of the water flow. The results obtained in this work indicate the need to take into account the contribution of capillary waves in the energy analysis of the initial stage of water erosion on slopes.