The fluid can't be "easily" simulated. It's a chaotic system (turbulent flow is chaotic). Even tiniest differences between the real and simulated state will ad

The fluid can't be "easily" simulated. It's a chaotic system (turbulent flow is chaotic). Even tiniest differences between the real and simulated state will add up and amplify over time. Fluid simulation is a notoriously hard problem. We don't have a solution to Navier-Stokes equations. Practical implementations have limited resolution in time and space, and plenty of simplifying assumptions.