Final Project
Introduction to the Desktop Wind Tunnel Project
The goal of this project is to design and build a compact desktop wind tunnel suitable for testing the aerodynamic properties of small objects. This wind tunnel is designed with both functionality and accessibility in mind, making it an ideal educational tool for high school students and science educators.
Dimensions and Materials
The main tunnel of the wind tunnel will be constructed from CNC-machined 10mm plywood. The tunnel will measure 500mm in length and feature a square cross-section with dimensions of 150mm by 150mm. A viewing window will be incorporated into the tunnel to allow for visual observation of airflow patterns and object interaction.
Laminar Flow
To achieve laminar flow, the wind tunnel will include a 100mm-long strainer positioned at the entrance of the tunnel. The strainer will feature a honeycomb pattern and measure 149.5mm by 149.5mm to fit snugly within the tunnel. This component will be 3D printed using a Bambulab A1 3D printer. Additionally, a finer wire mesh will be placed in front of the strainer to further eliminate any turbulence.
Airflow Generation and Control
Airflow will be generated using a PC fan with a PMT output and four wires. This fan will be powered by a PC power supply, ensuring a reliable and consistent source of energy. The airflow will be monitored and controlled using an Arduino microcontroller, providing precise regulation for experiments.
Visualization and Measurement
A smoke stream will be integrated into the wind tunnel to visualize the airflow around test objects. For more detailed analysis, the setup will include sensors to measure strain or lift, allowing for the observation of movements and forces acting on the object. These features will enable users to gain deeper insights into aerodynamics.
Educational Purpose
This project aims to serve as an educational resource, demonstrating the principles of fluid dynamics and aerodynamics. Its accessible design ensures that it can be replicated by science educators, providing a hands-on learning experience for high school students. The wind tunnel’s compact size and straightforward construction make it a practical tool for classroom demonstrations and experiments. By combining CNC machining, 3D printing, and microcontroller integration, this project showcases a multidisciplinary approach to engineering and design, encouraging curiosity and innovation in STEM education.
My first sketchs
Main Tunnel thoughts and Ideas
The main tunnel is designed so that anyone can rebuild it. I kept the joints as simple as possible. I could have gone ahead with the idea of using M6 screws along the sides, which I may still do for prototyping purposes, making it easier to take apart. The issue is that when using screws, you may run into leaks that could cause turbulence in the tunnel, defeating the purpose of having laminar flow. This is also why the window must have a tolerance of +0.3mm. The window needs to fit exactly in order to minimize leaks and be flush with the tunnel walls. Below, you can download the STL and DXF files.
The Honeycomb
Creating the honeycomb was not a task that could be accomplished simply by repeating the pattern in
a regular form. The first thing I did to achieve the desired pattern was to understand that it requires
two paths to follow. One path goes straight, while the other needs to be set at a 60° angle to the straight
path. I initially tried copying and offsetting the pattern, but the result wasn't satisfactory
and introduced a lot of errors. If even one part is slightly off, it creates a noticeable gap.
For the airstrainer, this would be especially problematic if the goal is to achieve laminar airflow.
I realize that there is a lot of math involved in coming up with a working airstrainer. I will not be getting
into this in much detail. Typically you are trying to ensure that air flows smoothly and evenly while avoiding
turbulence or flow disruption. This process involves several factors, including the velocity of airflow.
CAD Shots
