In our simulation, we patched the cells behind the cylinder to have a starting velocity of .2 m/s so that we would get the vortex shedding earlier. This also allowed us to better see the oscilliation of the lift coefficient as flow time increased.
In order to effectively capture the vortex shedding, a small enough timestep was needed. It was recommeded to have roughly 20 - 25 timesteps per cycle hence we used a timestep of .2. The resulting plot in the numerical results showing how the lift coefficient oscillated due to the vortex shedding is shown below. To compare the effect of the timestep size, we continue to plot the lift coefficient after the oscillations have been established with a timestep of .02 seconds.
Timestep = .2 s
Timestep = .2 -> .02s
We also run the simulation with a timestep of 1s. Notice how we see a smooth curve for the lift coefficient, rather than the oscillations due to the vortex shedding.
Timestep = 1s
The Strouhal Number from the literature is reported to be .183. We expect that the Strouhal Number will be roughly .2 for flow past the cylinder.
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