Can you help me a demo of Navier-Stockes equation solver?

I'm an engineer, please help me a demo of Navier-Stockes equation solver, thanks.

Could you please elaborate on what you want? You first post isn't very detailed.

It looks like section 9.8 of this book Mathematical Tools In Computer Graphics With C# Implementations goes over Navier-Stokes and has a full C# implementation.