[HectorRedal]

Hi,

I would like to know how to measure / determine when a vortex karman shedding pattern has been established in an horizontal flow past a circular cylinder. What parameter is measured so as to determine when the vortex shedding has been onset?

I was tryiing to simulate a flow past a circular cylinder with a horizontal velocity, and initially I was measuring the frequency of the vertical velocity. I assumed that when the frequency of this vertical velocity is greater than zero, the karman vortex shedding has been onset.

But, after having read this reference, http://www.leb.eei.uni-erlangen.de/w...1/pdf/0116.pdf, I have some doubts about what really I was measuring.
Maybe, the condition for the onset of the vortex shedding is not having frequency of the vertical velocity different than zero, but observing a repeating pattern of swirling vortices.

Then, only by observation of the flow, this can be determine, can't it?

Any reference I can take a look at is welcome / appreciated.

Thanks.

Best regards,
Hector.