Heaving Homemade Buoys: A Project Leveraging Smart Phone Movies and MATLAB-Basd Image Processing to Teach Dimensional Analysis in an Undergraduate Fluid Mechanics Course

Hans Mayer; Andres Elzaurdia; Christian Clephan; Arturo Flores

Download Paper | Permalink

Conference: 2022 ASEE Annual Conference & Exposition
Location: Minneapolis, MN
Publication Date: August 23, 2022
Start Date: June 26, 2022
End Date: June 29, 2022
Conference Session: Experimentation and Laboratory-Oriented Studies Division Technical Session 3: Best of ELOS
Page Count: 19
DOI: 10.18260/1-2--40469
Permanent URL: https://peer.asee.org/40469
Download Count: 268

Paper Authors

biography

Hans Mayer California Polytechnic State University, San Luis Obispo

visit author page

Dr. Mayer holds a BSME degree from Cal Poly SLO, a MS degree in ME from Carnegie Mellon University, and a PhD in ME from the University of California at Santa Barbara. Prior to starting his tenure-track appointment at Cal Poly SLO in 2019, he was a lecturer for nine years at that same school.

visit author page

author page

Abstract

We live in a modern world where students have access to incredible tools that can record and process data quite literally at their fingertips in the form of a smart phone. Why not leverage that tool for hands-on experiments in undergraduate engineering courses? The pandemic has taught us that we need to be flexible in our shift and adoption of options that can bring hands-on learning opportunities to students while using limited resources. In this paper we document a project to help facilitate teaching the utility of dimensional analysis. Often this topic is discussed only briefly in a fluid mechanics course and most traditional textbook problems shy away from providing the data sets that dimensional analysis can shed light on. In contrast to this traditional approach, our project involves students performing experiments at home and with minimal resources, uses smart phones to extract data, and then crowdsources data. This data drives the discussion of how dimensional analysis can be used to look for trends and predictive relationships in experimental results. In our project, students are asked to create a simple buoy using “around the house” materials. They start with a bottle, can, or container, and to create a stable buoy, mass is added. We have seen students use sand, dirt, rice, and small rocks – all will work. A wide range of container sizes and masses can be sourced by a creative group of students. A spherical marker is then attached to the buoy to aid tracking. Finally, students are asked to use their smart phone to record a movie of the buoy as it oscillates vertically, i.e., heaves, in a pool of water such as a filled sink, bathtub, or bucket. The authors have also recorded movies of buoys in other liquids (with different density) to supplement student experiments in water. Once an experiment is complete, students use a MATLAB program (developed by undergraduate students) to identify and track the buoy marker through each movie frame. The output from the code includes plots of the heave oscillations. With this information, the code reports basic statistics that describe the motion. Students now have experimental data that can be shared with classmates and the instructor (or even across universities in a collaborative way). This data can facilitate a guided discussion of the utility of dimensional analysis synchronously in lecture or asynchronously in a homework problem or project. When presented in dimensional form of one variable against another, (e.g., heave frequency versus mass) students can see the hint of trends but also recognize the influence of other variables (cross sectional area or fluid density). However, when dimensional analysis is used to create relevant dimensionless groups, the result is a collapse of the data to show a predictable trend. The rationale of using a heaving buoy as a case study, beyond the simplicity for home-based experiments, is that an accessible analytical solution exists for comparison (appropriate with the level of the fluid mechanics course).

Citation
Format

Mayer, H., & Elzaurdia, A., & Clephan, C., & Flores, A. (2022, August), Heaving Homemade Buoys: A Project Leveraging Smart Phone Movies and MATLAB-Basd Image Processing to Teach Dimensional Analysis in an Undergraduate Fluid Mechanics Course Paper presented at 2022 ASEE Annual Conference & Exposition, Minneapolis, MN. 10.18260/1-2--40469

TY - CPAPER
AB - We live in a modern world where students have access to incredible tools that can record and process data quite literally at their fingertips in the form of a smart phone. Why not leverage that tool for hands-on experiments in undergraduate engineering courses? The pandemic has taught us that we need to be flexible in our shift and adoption of options that can bring hands-on learning opportunities to students while using limited resources. In this paper we document a project to help facilitate teaching the utility of dimensional analysis. Often this topic is discussed only briefly in a fluid mechanics course and most traditional textbook problems shy away from providing the data sets that dimensional analysis can shed light on. In contrast to this traditional approach, our project involves students performing experiments at home and with minimal resources, uses smart phones to extract data, and then crowdsources data. This data drives the discussion of how dimensional analysis can be used to look for trends and predictive relationships in experimental results. In our project, students are asked to create a simple buoy using “around the house” materials. They start with a bottle, can, or container, and to create a stable buoy, mass is added. We have seen students use sand, dirt, rice, and small rocks – all will work. A wide range of container sizes and masses can be sourced by a creative group of students. A spherical marker is then attached to the buoy to aid tracking. Finally, students are asked to use their smart phone to record a movie of the buoy as it oscillates vertically, i.e., heaves, in a pool of water such as a filled sink, bathtub, or bucket. The authors have also recorded movies of buoys in other liquids (with different density) to supplement student experiments in water. Once an experiment is complete, students use a MATLAB program (developed by undergraduate students) to identify and track the buoy marker through each movie frame. The output from the code includes plots of the heave oscillations. With this information, the code reports basic statistics that describe the motion. Students now have experimental data that can be shared with classmates and the instructor (or even across universities in a collaborative way). This data can facilitate a guided discussion of the utility of dimensional analysis synchronously in lecture or asynchronously in a homework problem or project. When presented in dimensional form of one variable against another, (e.g., heave frequency versus mass) students can see the hint of trends but also recognize the influence of other variables (cross sectional area or fluid density). However, when dimensional analysis is used to create relevant dimensionless groups, the result is a collapse of the data to show a predictable trend. The rationale of using a heaving buoy as a case study, beyond the simplicity for home-based experiments, is that an accessible analytical solution exists for comparison (appropriate with the level of the fluid mechanics course).
AU - Hans Mayer
AU - Andres Elzaurdia
AU - Christian Clephan
AU - Arturo Flores
CY - Minneapolis, MN
DA - 2022/08/23
PB - ASEE Conferences
TI - Heaving Homemade Buoys: A Project Leveraging Smart Phone Movies and MATLAB-Basd Image Processing to Teach Dimensional Analysis in an Undergraduate Fluid Mechanics Course
UR - https://peer.asee.org/40469
DO - 10.18260/1-2--40469
ER -