[wwbbit]

I am simulating the synthetic jet on NACA 0015 airfoil.
so I have a suction/blowing type boundary condition, and a prescribed velocity distribution is imposed at the boundary:
y=47.95*sin(2*pi*50*time). It's normal to the patch.
I have a groobyBC type boundary condition in my ./0/U, the code is

jet// the patch name
    {
    	type		groovyBC;
	valueExpression		"47.95*sin(2.0*pi*50*time())*normal()";
	value		uniform (0 0 0);
    }

Meanwhile, I have a probe code in system/controlDict, here it is

functions 
( 
probes1
    	{
        // Type of functionObject
       		type probes;
		log	true;
		outputControl timeStep;
		outputInterval 1;

        // Where to load it from (if not already in solver)
        functionObjectLibs ("libsampling.so");

        probeLocations
        (
            (0.045 0.02338 0.01875)// the point near the patch
        );

Now, the problem is magnitude of the velocity vector is far greater than 47.95, some of the vector is

 
//time Ux Uy Uz
0.04486             (79.4339 -16.8528 -3.46622e-21)
      0.04488             (77.6659 -15.7305 -4.04792e-21)
       0.0449             (75.7184 -14.4926 -4.59096e-21)
      0.04492             (73.599 -13.1451 -5.092e-21)
      0.04494             (71.3162 -11.6939 -5.54669e-21)
      0.04496             (68.8783 -10.1458 -5.9491e-21)
      0.04498             (66.2938 -8.50744 -6.29237e-21)
        0.045             (63.5716 -6.78616 -6.57194e-21)
      0.04502             (60.7203 -4.98953 -6.77717e-21)
      0.04504             (57.7497 -3.12517 -6.89967e-21)
      0.04506             (54.6711 -1.19994 -6.92882e-21)
      0.04508             (51.4999 0.781713 -6.85615e-21)
       0.0451             (48.2558 2.81933 -6.68789e-21)
      0.04512             (44.9628 4.91865 -6.43502e-21)

I have no idea about the error!! Please help me !
Any hints very much appreciated!
Regards
wwbbit