Hi

I am running LES simulation with periodic boundaries. I am monitoring velocity at a point in my domain. I observe steady increase in my velocity. Why is that?? Any input will be welcome.

Thank you

If your scheme is not energy conserving, instabilities could cause one component say u-velocity to rise and then to satisfy divergence the other two components also increase. And the downhill begins.

You can look up papers on "energy conserving schemes" for more information.