Date of Award

2016

Degree Type

Thesis

Degree Name

M.Sc.

Department

Civil and Environmental Engineering

First Advisor

Bolisetti, Tirupati

Second Advisor

Balachandar, Ram

Rights

CC BY-NC-ND 4.0

Abstract

Evaporation is an important component of hydrological cycle. With rising global temperatures it is important to gather knowledge about evaporation and the physics involved. In this investigation, the evaporation from fully saturated bare soils was conducted to determine the drying process of porous media. It is defined that evaporation from fully saturated bare soils is categorized into two main stages Stage 1 and Stage 2 and an intermediate stage called the falling rate period. The evaporation process from fully saturated porous media begins with Stage 1 evaporation. At this stage the evaporation is constant with high evaporation rate, this is caused by the capillary action transporting the water molecules up to the surface of the porous media. Next, the evaporation enters the falling rate period where the evaporation drops over time with capillary forces growing weaker. After the falling rate period the evaporation enters Stage 2 evaporation where the evaporation rate is really low. In this investigation, experiments were conducted in order to gather a database to predict the evaporation model based on the ambient and soil conditions. The investigation was done using both traditional method of evaporation estimation and infrared imagery. Infrared imagery was introduced as a non-intrusive way of determining the temperature changes of the surface of the porous media. The experiments also focused on the evaporation behaviour due to different boundary conditions and variety of turbulent air flow velocities. A mathematical model was used to analyse the evaporation rates as a function of temperature, air flow velocity, humidity and porous media characteristics. The model was able to predict the observed evaporation rates successfully during Stage 1 and Stage 2 evaporation.

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