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How to calc time devirative of a scalar

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Old   June 23, 2006, 04:42
Default I want to do a volume average
chris book
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I want to do a volume average of volScalarField and from this scalar I want to calc the time devirative.

I have tried:

scalar dpmdt = ddt(p.weightedAverage(mesh.V()).value());

but the ddt function does not allow a scalar argument.

How can I do this?
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Old   June 23, 2006, 13:50
Default Basically, by hand: store seve
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Hrvoje Jasak
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Basically, by hand: store several scalars and calculate the ddt directly from their values. A scalar variable is just a float (or a double) and it does not record its own history.

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