At home, do-it-yourself fluid mechanics

There were many disruptions in the educational system caused by the COVID-19 Pandemic.

Scientists from the University of Illinois at Urbana-Champaign describe their work with students in a book. rheology is a type of physics that is used to study the way non-Newtonian liquids or semisolid substances flow.

When force is applied, non-Newtonian fluids can change shape. Sometimes they respond with plastic flow. Simple rheometric measurements can be carried out at home to measure quantities such as viscoelasticity.

Randy Ewoldt, the professor involved in developing the course, initially called the project Shelter-in-Place rhometry due to the acute nature of the COVID-19 Pandemic.

Qualitative visual evidence of rheological properties and quantitative measurements were part of the project assigned to the students. The students looked for shear thinness, viscoelasticity, shear normal stress difference, and extensional viscosity.

The students were able to carry out their measurements even without laboratory rheometers. buttercream frosting, toothpaste, yogurt, peanut butter, mayonnaise, egg whites, and many other substances were studied by them.

A student, Ignasius Anugraha, developed a compression squeeze flow analysis to study buttercream frosting. The frosting was placed between two cardboard discs and subjected to force by stacking ramekins filled with water atop the discs.

The frosting was able to support the weight of the water until a critical value was reached, at which point the frosting collapsed on one side and squeezed out. The yield stress is a quantity measured using equations involving the weight of the water.

A student named Max Friestad created an experiment to study a behavior called gravity-driven filament stretching. A tube of toothpaste was suspended vertically and gently squeezed by Friestad. Using a cellphone with a high-speed frame-rate camera, Friestad was able to calculate the extensional viscosity.

The course was so successful that it is still offered by the faculty.

We are currently working on a review of methods which we believe will be useful not only for coursework and instruction but also for research and technical communication.

M. Tanver Hossain and Randy H. Ewoldt wrote the article. The article will appear in the journal on May 10, 2022.

More information: Do-it-yourself rheometry, Physics of Fluids (2022). DOI: 10.1063/5.0085361 Journal information: Physics of Fluids Citation: At home, do-it-yourself fluid mechanics (2022, May 10) retrieved 10 May 2022 from https://phys.org/news/2022-05-home-do-it-yourself-fluid-mechanics.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.