Project Description: This four-person project was the final experiment for my Fluid Mechanics lab in Spring 2022, where we had to come up with our own experiment utilizing either a wind tunnel or pipe flow system. My group decided to investigate a possible correlation between top speed and drag coefficient of three different land mammals: a cheetah, a horse, and a cow.
Software Used: Meshmixer, Excel (for data analysis)
My Role: I prepared and 3D printed our scaled down animals, which included adding threads for mounting them to the wind tunnel sensors, and I calculated drag coefficients by compensating for the front-facing area of our objects.
Other Roles: Other members of the team worked on developing and executing experiment procedures to facilitate data collection for our experiment, in addition to writing other sections of our lab report.
Big Wins: Our models attached to the dynamometer sensor very cleanly and easily and fit though the wind tunnel access port without issue. These were challenges for several groups who didn’t plan ahead with their test objects.
Challenges: The models that we used in testing did not reflect the animals in their running form, which was an oversight that reduced the validity of our conclusions regarding drag at top speed.
Key Takeaways: Scale models are a great scientific tool – but only if you account for scale-dependent behavior when attempting to draw conclusions for the original objects.
This image shows the upper and lower sections of the dynamometer in the wind tunnel. The upper image shows our cow model being threaded onto the stand so we can measure drag forces
Here are the three models I made for testing in this experiment. The animals were at different scales, but made as large as possible for fitting within the wind tunnel to have the highest resolution on drag force differences.
This plot shows our measured and calculated results. There may be a trend, but we had massive uncertainty in our calculations, and also should have modeled animals in their sprinting form.