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  • FLUENT - Unsteady Flow Past a Cylinder - Step 5

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We can see a clear sinusoidal pattern, a sign of sustained vortex shedding process after 40s.This plot can be used to compute the correct value of Strouhal number. The problem is non-dimensionalized (D = 2, U = 1) and Sr = f*D/U = 0.0846 * 2 = 0.169. The results matches fairly well with the value (0.183) as reported by Williamson (link)

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titleCalculating Shedding Frequency

To accurately calculate the shedding frequency, take an average of at least 10 shedding cycles (e.g 10 Cl peak) . Also, open the cl-history file (saved previously in the same location where the original mesh was read) and plot the data using excel for better data representation and graphing option. An example of Lift Convergence Plot plotted using excel is shown below:
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https://confluence.cornell.edu/download/attachments/107011456/Excel%20Lift%20convergence.jpg

 

 
Main Menu > File > Write > Case & Data...
Use the default name (Mesh's file name "cylinder") and click OK.

 

Go to Step 6: Analyze Results

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