Figure 5. Drag force plotted against air flow speed: (a) measured on ball model and sting and on sting alone; and (b) adjusted for tare drag.
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The measured drag forces were adjusted for tare drag and can be seen in Figure 5b. Generally, the drag force increases with air flow speed, as one would expect (for simple situations drag varies with the square of wind speed). However, there is a small fluctuation in the drag force at low speeds. There was found to be no major effect on the drag due to ball orientation as each run of tests gave very similar results.