ELi5 Why are CFD and wind tunnels used together for flight simulation

Question

I am wondering why there aren’t full simulations using CFD for flight.

In: 4

Answer 1

Because fluids are notoriously difficult to predict.

So difficult that there is an ongoing $1,000,000 bounty for anyone who can make *any* headway in understanding the fundamentals of turbulent fluid flow.

So while we can make some simulations that are very good, and don’t take too much processing power, there is no replacing a physical model.