Numerical Simulation of Flow Past a Circular Cylinder

4 Numerical Simulation of Flow Past a Circular Cylinder 

It is readily evident that this time te, reduces rapidly as the Reynolds number increases beyond Recr2- Also as one approaches Rccri from above, te increases in almost an unbounded manner. We emphasize that the periodic variation of lift was obtained without any artificial excitation, as has been done in many previous investigations. This figure qualitatively displays the fact that the instability and its supercritical saturation changes when the Reynolds number transits through Recr2- 

To understand better the qualitative and quantitative changes as the flow transits through Rcgri and Rccr2, in Fig- 5.3, we have plotted the computed asymptotic amplitude Ag, for different Reynolds numbers, shown by discrete symbols. In Drazin Reid (1981), (Tj- is approximated to k Re — Reari) and thus Eqn. (5.1.9) becomes. 

Ag varies qualitatively as, where e = Re — Re r- We have drawn three continuous lines (to represent different segments of Fig. 5.3) that can be parametrically represented as 

The solution as given by Eqn. (5.4.1), contains only the first term of Eqn. (5.4.2). Also note that in describing this variation, the Recr used 

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