Abstract
In this work, using a mathematical model and numerical simulation, we investigate the effect of time-dependent evaporation rates on stripe formation inside containers. This pattern formation is driven by the coffee-ring effect. The coffee particles inside a container move according to random walk and under the gravitational force. Because of the time-dependent evaporation rate, we can observe stripe formation inside a container after evaporation of the coffee particle-laden liquid. Various numerical experiments are performed to demonstrate the proposed model can simulate the stripe formation in a container.
Highlights
When a drop of coffee evaporates on a solid substrate, the coffee particles form a ring-like stain at the contact line
This phenomenon is a consequence of faster evaporation at the contact line, driving the coffee particles to convectively migrate toward the contact lines [1], which is known as the coffee-ring effect [2,3,4]
The physical phenomenon related to the coffee-ring effect has been researched in several experiments withal various colloidal suspensions containing nanoparticles [5,6,7,8,9,10], air bubbles [11], quantum dots [12,13,14], biological fluids [15,16,17,18,19,20,21], bacteria [22,23,24]
Summary
When a drop of coffee evaporates on a solid substrate, the coffee particles form a ring-like stain at the contact line. The coffeering effect has been investigated in various numerical experiments based on the Monte Carlo method [46,47,48,49,50], finite element method [51, 52] or finite difference method [53]. The objective of the present work is to suggest the mathematical model without the capillary flow that focuses on investigating a diffusion process of the Brownian particles under gravitational force and to perform various numerical experiments to demonstrate the proposed model can simulate the coffee-ring effect inside containers with time-dependent evaporation rate.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
