resistance=(8*viscosity*length)/(3.1416*(radius^4)) sysphs fluidFlow=pressureDiff/resistance sysphs pressureDiff=opening2Pressure-opening1Pressure sysphs opening1FluidFlow+opening2FluidFlow=0 sysphs fluidFlow=opening1FluidFlow sysphs pressure=gravity*fluidHeight*fluidDensity sysphs der(fluidHeight)=-fluidFlow/surfaceArea sysphs