Dear all,

This is not an answer, nor a solution. Just wanted to share an observation from running a parallel simulation, which should converge to a stationary solution I observe a kind of random variation in the kinetic energy - which matches the "low amplitude, random" description of Fernando. I thought it comes from the outflow condition I am using, or the high order modes, and I ignored it.

Best,

Stan

Dear all,

When running parallel (72 core) aggregate quantitities such as body forces (particularly pressure forces) seem to include a certain degree -low amplitude- of randomness in their evolution. The high frequency random oscillations seem to be of the order of the sampling period. This suggests some kind of issue with the gathering of data from all parallel processes for aggregate quantity computation.

Is there some precaution that must be taken upon compilation or in defining the cluster parallel environtment to avoid this issue?

I attach one such forces time-series to illustrate this. Viscous forces seem to be just fine, while pressure (and total) forces oscillate at high frequency.

Cheers

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