how to monitor the plusant velocity using swak4Foam
 

hello everyone!

i want to output the pluse velocity during calculating time,so i insert the some functions to the ControlDict, they are as follows,

fieldAverage1
{
type fieldAverage;
functionObjectLibs ( "libfieldFunctionObjects.so" );
outputControl outputTime;
enabled true;

fields
(
U
{
mean on;
prime2Mean on;
base time;
}

);
}
uix
{
type expressionField;
autowrite true;
expression "U.x-UMean.x";
outputControl outputTime;
dimension [0 1 -1 0 0 0 0];
fieldName uix;
}


but when i run the programe, the error are as follows,

--> FOAM FATAL ERROR:
Parser Error for driver FieldValueExpressionDriver at "1.5-9" :"field UMean not existing or of wrong type"
"U.x-UMean.x"
^^^^^
why UMean not existed? i also use the fieldaverageFunction to output it

anyone can help me?

best wishes!

ziyang