[manuc]

Hello All

I am interested to monitor the value of my field at center of my geometry and create a field at each time step, which is equal to the product of the field at that location with the value of the field at the center of the domain. I would like to know if there is any intrinsic function like pos() which could help me to have:

 C(x,y,z,t) =T(x,y,z,t)* T(x0,y0,z0,t)

How can I access a specific point (x0,y0,z0) and use it in expressionfield.
This issue was solved with the help of the thread below
groovyBC and probe measurement


Now my aim to calculate the product of the velocity (y component) at the sensor1 (see below) with the Y-velocity in a particular plane

What I tried
Create a cloud point.

functions
   	{    

		createMeasurement 
		{ 
			type createSampledSet; 
			outputControl outputTime; 
			outputInterval 1; 
			setName sensor1; 
			set  { 
					type cloud; 
					axis xyz; 
					points ( 
					(0.01 0.05 0.05) 
					); 
          		 }      
		 }
......

Try1: Create a 3Dfield with the calculation that I need. i.e. multiplying the value from cloudpoint with U.y in the whole domain

UpCorr
            {
             functionObjectLibs ("libswakFunctionObjects.so");
			 type              expressionField;
 			 outputControl     timeStep;
                 outputInterval    1;
                 variables         ("UpL{set'sensor1}=(U-            							UMean);");   
                 expression        "U.y*UpL.y";
                 fieldName         UpCorr;
                 verbose           true;
                 autowrite         true;

            }

The issue is I only need to do the above calculation at a single plane. But now I am forced to save/calculate for a 3D field.
What I tried and failed
Create a plane as in swakexpression tutorials calculation but try with type expressionfield .

functions
{
....
UpCorr2
		 {
    		 functionObjectLibs ("libswakFunctionObjects.so");
                 type        expressionField;
    			 valueType   surface;
    			 surfaceName aperturePlane;
   			 surface
    				 {
     				     type             plane;
       			     basePoint        (0.01 0.05 0.05);
        			     normalVector     (0 1 0);
                          interpolate       true;
                      }   
                 variables         ("UpL{set'sensor1}=(U-            							UMean);");   
                 expression         "U.y*UpL.y";
                fieldName           UpCorr2;
                outputControlMode   timeStep;
                outputInterval      1;
                verbose             true;
                autowrite         true;

            }
....
}

But this creates a 3D scalarfield. What I expect is just a 2D field (just for the plane). Can someone help me to do it just for the plane

Thanks in advance