Optimization of Riblets on Bicycles Jason Ryan Image Source Image - - PowerPoint PPT Presentation

Optimization of Riblets

• n Bicycles

Jason Ryan

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Project Summary

• Goal

▫ Validate the concept of using aerodynamic riblets to reduce drag on a bicycle

• Outcomes

▫ Quantify the drag reduction from applying riblets in the flow regime experienced by bicycles ▫ Determine the most influential riblet parameters for drag reduction

Customer Needs

Customer Need # Importance Description CN1 1 Reduce drag on the bicycle CN2 1 Retain function as a bicycle CN3 1 Quantify the drag reduction on bicycles due to the application of riblets CN4 1 Determine the most critical riblet parameters for drag reduction CN5 1 Process to construct prototypes needs to accommodate multiple designs CN6 1 Prototypes should be able to meet tolerances CN7 1 Measure drag on the bicycle CN8 2 Be able to measure wind speed and characteristics while measuring drag CN9 2 Non-abrasive to rider CN10 2 Material needs to be durable CN11 2 Weather resistant CN12 2 Low cost

Benchmarking

Reynolds Number Riblet Height (in.) Skin Friction Reduction (%) Total Drag Reduction Nasa SuperSonic Test 1 (Source) 2-3.4 million 0.003 4-8%

• Nasa SuperSonic

Test 2 (Source) 3.6-6 million 0.0013 4-15%

• National

Aerospace Labs Report (Source) 3.5-6 million (Re/ft) 0.033-0.152 (mm) 5-8% 2-3%

From Research Articles

Engineering Analysis

• 1. Drag from Frontal Area Change (0.45%)
• 2. Reynolds Number (1.76 x 104 – 9.4 x 104)
• 3. Dimensional Analysis Air to Water
• 4. Force Concentrations from Riblets

Potential Concepts- Riblet Design

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Potential Concepts - Prototype

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Potential Concepts - Measurement

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Staffing

• 3 ME

▫ Aerodynamics ▫ Data Aquisistion ▫ Materials

• 1 ISE

▫ Materials / Manufacturing

• Sayer Murphy

▫ ID Student