P14414Arborloo Wind Resistance Test Stand Final Presentation 13 May 14

Overview Team Introduction Project Objectives Customer/Engineering Requirements Systems Architecture Theory CFD Analysis Design Results Project Improvements & Recommendations MSD Assessment

Team Introduction

Project Objectives Design a test stand to determine the wind resistance of various scale model arborloo designs Provide information about the forces experienced by an arborloo during a Class I hurricane Allow for safe testing of various arborloo sizes, shapes, and materials Team should create a set-up for testing, devise a test procedure, and provide recommendations for the optimal arborloo shape and design based on testing results

Customer Requirements

Engineering Requirements

System Architecture

Theory CD – Drag Coefficient The drag coefficient is a dimensionless parameter that characterizes an object's resistance to fluid flow and allows for direct comparison of aerodynamic effects on different shapes. For certain shapes, the Coefficient of Drag stays constant independent of Reynolds Number. In the case of the team’s first prototype, which can be treated as a flat plate, the CD will stay constant for all Re larger than 1000.

CFD Analysis

Design Utilizes existing wind tunnel base 2 x Clippard EMC-12 pressure scanner Omega PX277 pressure transducer JR3 load cell National Instruments NI_USB-6008 DAQ Fabricated flange to accommodate existing shaft, base & wires Test Arborloo designed with ¼” PVC sheets

Final Design

Testing Testing Procedures Document <20 mins entire testing Automated Results plotting using MATLAB

Results

Results The force exerted on an arborloo by 95 mph winds is at the very best 415 lbf (CD = 1) and at worst 830 lbf. (CD = 2) Comparable to two male gorillas (330 lbf) sitting on face of the arborloo The pressure distribution shows that a larger stress is applied to the arborloo closer to the ground Pressure distribution similar to that seen in CFD, better resolution w/ more pressure taps

ER Revisited

Project Improvements/Recommendations Better understand the blockage effects in wind tunnels Future teams should use CFD and empirical results to determine correction factor Recommendations: It is clear from the collected data and knowledge of hurricane conditions, that the best way to ensure that the structure would not be destroyed is if the structure can be easily disassembled and stored away.

MSD Assessment Model MSD as a job search? Students bid on existing projects and interview w/ guide or cust. “What skill-set can you bring to the table?” Do not waste MSD I time with presentations, MSD I should be primarily working time as that’s when everyone is most motivated. Presentations were not helpful. MSD I was a little slow, long lead times for some small deliverables

Acknowledgments Special Thanks To: Sarah Brownell Dr. Thorn Prof. Wellin Dr. Venkataraman Plastic and Concrete Design Teams Pedro Cruz Dilone

Questions?