Dear JP, We have been using the constant flow rate feature in a number of cases as well, but we have not seen your problem. Maybe a more general question; why does the flow rate vary at all in your case? In all our cases, due to the implicit superposition of the Stokes solution, we get the flow rate exactly constant without fluctuations. Best regards, Philipp On 2015-03-26 10:40, [email protected] wrote:

Dear All,

I have setup a simulation with Nek's constant flow rate option. The simulation consisted of a number of restarts, in particular one restart was carried out on 16384 cores whilst all the other runs where on 8192 cores. In the plot of flow rate against dump in the following link, which I carry out with my post-processor, the flow rate oscillates strangely in the region where the run was on 16384 cores, i.e. between 220 and 343.

https://www.dropbox.com/s/fnfuqhj2nxbh5g5/FlowRate_restart_section.png?dl=0

Any idea on what might be causing this oscillation? All parameters, geometry, machine settings etc. have been left the same for the run on 16384 cores (except for changing the max no. of processors and max no. of elements per processor in SIZE).

Regards, JP

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