The Effect of Shape on Aerodynamic Drag

Overview

Objectives/Goals The objective is to determine the effect of shape on aerodynamic drag as measured in a homemade wind tunnel. After completing the first two years of work on the experiment (Phase I), the experiment was continued (Phase II) in order to accomplish the following objectives: 1) to improve the wind tunnel design, specifically to increase air velocity, 2) to devise a new method of measuring drag, 3) to calculate the drag coefficient, and 4) to gain a better understanding of the flow patterns around each object. Methods/Materials An eight foot long wind tunnel was constructed out of pine and plywood and powered by two box fans. Eight balsa wood objects, each with the same cross sectional area were formed. The amount of drag produced by each object was individually tested in the wind tunnel. The Drag Coefficient of each object was then calculated. Results The test objects ranged from a drag coefficient of 0.38 to 1.22, which represents a 31% drop in drag produced. In order from least to greatest drag produced, the objects are as follows: sphere, teardrop, sloped-diamond, sloped wedge, mini-van, wedge, diamond, and rectangular prism. Conclusions/Discussion The substantial difference in the amount of drag produced supports the hypothesis that if an object is designed to be streamlined, then it will produce less drag.

Competition history

• CSEF 2008 Applied Mechanics & Structures · Entry S0228

Resources

• CSEF project summary ↗

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