[cheng1988sjtu]

Hi Foamers:

Now I'm working on channelFoam to reproduce the log-law and turbulence intensity. I just finished my first try using dynSmagorinsky. However, I've got some problems about the post-Processing.

1.
in the log file, I found that
************************************************** ************************************************** *
Time = 10

............
Uncorrected Ubar = 0.1335 pressure gradient = 0.000133009
ExecutionTime = 172139 s ClockTime = 345743 s

Calculating averages
************************************************** ************************************************** **

Is the 'pressure gradient' normalized by 'rho' already? I've seem some threads about it and got confused. Basically I need to use it to calculate the wall shear velocity, so it's very important to understand that.

2. Although in the 'controlDict' file, we have fieldAverage, but It seems that it is just a time average in the UMean, Pmean files, so I have 2 questions on that: a.> iis it averaged from t=0? even if it's not steady state? b>. Is there any existing utility that I can use to take a surface average of U and P? BTW, I may need to take surface average at several planes, so maybe sampling is not such a good choice for me. Any suggestions?

Thank you, foamers!

Zhen