interDyMFOAM sloshingtank2d probe sample does not make sense
 

Dear all:

I am running a simple problem in interDyMFOAM, in sloshingTank2D. The tank is 2D (1mX1mX0.1m). The tank is subject to translation only with sinusoidal input. I have a probe close to the right wall of the tank and I am sampling the pressure at the probe. At time t=0 the tank is at rest. When I plot the force versus time, I see that at time t=0 the force is not zero but some positive value. How is this possible? Shouldnt the force at t=0 also be zero?

I look forward to your response / advise.