Wind Tunnel

(In progress)

The Wind Tunnel project is an ongoing effort to design and build a compact, open-loop aerodynamic testing system for educational and experimental use.

Objective

The objective of this project is to design and construct a semi-modular, open-loop wind tunnel capable of accurately measuring aerodynamic forces such as drag, lift, and side forces on scale models. The tunnel will prioritize flow uniformity and repeatable data collection, using integrated Arduino-based sensors to record real-time velocity, pressure, temperature, etc. Designed with mobility and practicality in mind, the system will feature a compact frame that can be easily disassembled for transport and storage while maintaining structural rigidity during operation. CAD modeling and CFD analysis in SolidWorks and ANSYS will guide the optimization of diffuser angles, contraction ratios, and fan placement to achieve smooth, laminar airflow. Once complete, the tunnel will provide a reliable platform for aerodynamic testing, model validation, and hands-on research in fluid dynamics. This project is being developed as part of a larger goal to support future research in vehicle aerodynamics, wing design, and propulsion system efficiency.

Requirements

Goals

Develop a compact open-loop wind tunnel for aerodynamic testing of scale models and vehicle components.
Measure drag, lift, and side forces using integrated Arduino-based sensors and load cells.
Capture real-time airflow data (velocity, pressure, and temperature) for analysis and calibration.
Achieve test-section airspeeds up to 20 m/s (≈45 mph) under controlled conditions.
Use CFD simulations (SolidWorks / ANSYS) to optimize contraction ratio, diffuser angle, and flow conditioning.
Design a semi-modular frame that can be disassembled for transport and storage.
Incorporate acrylic or polycarbonate panels for optical access and flow visualization (e.g., smoke or tufts).
Power the system with a single high-static-pressure fan, optimized for flow uniformity and noise reduction.
Maintain stable operation for continuous runs up to 5 minutes without overheating or fan instability.
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Design Development

Initial Concept Calculations

The design process began with establishing key geometric parameters and chamber ratios to achieve smooth, uniform airflow through the test section. Early concept sketches and calculations focused on defining the dimensions of the inlet, contraction, test, and diffuser chambers based on aerodynamic efficiency and manufacturability. A 5th-degree polynomial contraction profile was selected to minimize boundary layer separation and pressure losses, while diffuser walls were angled at 7° to promote stable flow recovery. Each section’s geometry, including inlet area, test section ratio, and chamber lengths, was derived through iterative analysis to balance performance with the constraints of an open-loop system.

CAD Designs

The wind tunnel geometry was modeled and refined in SolidWorks through multiple design iterations, focusing on aerodynamic efficiency, manufacturability, and structural stability. Each stage of development addressed weaknesses observed in previous versions, while preserving smooth flow transitions and modularity for easy transport and upgrades. The models also served as a foundation for CFD analysis, ensuring the final tunnel maintains uniform flow distribution, minimal turbulence, and ease of assembly.

1st Iteration

The initial CAD model established the overall form factor of the open-loop tunnel, including the inlet, contraction, test, and diffuser chambers. This version focused primarily on defining chamber proportions and the curvature of the contraction section. While effective for spatial layout and airflow path visualization, it lacked structural reinforcement and mounting features for sensors, highlighting areas for mechanical and aerodynamic improvement.

2nd Iteration

The second iteration introduced structural bracing to improve rigidity under load and maintain precise alignment between chambers. The flow-conditioning screens were integrated into the design to enhance flow uniformity entering the test chamber. Additional areas were included for installing instrumentation and future upgrades. The base structure acts as both a stand and an area to install electronics and sensors.

Electronics

This part of the build is in progress — photos and data will be added once testing is complete.

Parts List (Changes to be made)

The wind tunnel’s components were carefully selected to balance performance, accuracy, and cost efficiency while maintaining modularity for future upgrades. The current design prioritizes reliable airflow generation, precise aerodynamic measurement, and robust data acquisition using Arduino-based control and sensing systems. Each component, ranging from the high-static-pressure fan to the differential pressure and load sensors, was chosen to ensure repeatable testing conditions and ease of integration with the data collection interface.

Prototyping & Fabrication

Scale Prototype

A 24% scale protype of the wind tunnel prototype was fabricated to validate the CAD model’s geometry, ensuring accurate representation of the contraction, test, and diffuser sections before full-scale construction. A prototype was 3d printed using PLA, allowing for rapid testing of contraction and diffuser transitions as well as assembly fit. The design was scaled proportionally to preserve flow characteristics while minimizing print time and material cost.

3d Print File

The digital slicing stage in the 3D printing workflow defined the orientation, scale, and print supports of the model. The wind tunnel was sectioned and arranged to minimize warping and ensure the contraction and diffuser curves printed cleanly.

3d Printing

Layer adhesion and tolerance testing ensured that the contraction and test chambers could be printed as continuous, sealed volumes. Real-time adjustments to speed, temperature, and support placement improved print quality and minimized post-processing time.

The first assembled prototype was used to evaluate fit, proportion, and airflow pathway alignment. The open-loop tunnel was supported by a lightweight frame that replicated full-scale mounting conditions. This version provided an initial physical sense of scale and helped assess stability and flow uniformity.

The final scaled prototype incorporated reinforced walls, a larger base for stability, and an integrated fan inlet for consistent airflow entry. Its modular structure allows for easy transport and sensor integration during early calibration tests. This version represents the optimized configuration that will inform full-scale fabrication and CFD validation.

This part of the build is in progress — photos and data will be added once testing is complete.

Testing & Validation

This part of the build is in progress — photos and data will be added once testing is complete.

Results & Analysis

This part of the build is in progress — photos and data will be added once testing is complete.

Potential Improvements

This part of the build is in progress — photos and data will be added once testing is complete.

Technical Skills Applied

This part of the build is in progress — photos and data will be added once testing is complete.

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