Function
 

Hi every body
I need to find dynamic pressure so i wrote a this function:
${TotalPressure}[2]-${StaticPressure}

but its doesn't work. how i should do that?

get rid of the [2]. also depending on your model $Pressure is fine rather than static - read about all the pressure types here: Simulating Physics > Flow and Energy > Pressure

OK so how i can find center of this pressure(hydrodynamic)?
my problem is a boat moving forward .its asymmetric problem so center of presser is not in the middle .i want find to longitudinal and horizontal distance of center of pressure respect to center of gravity.