AFT Blog
Jack, Ryan, and Sally are piloting a small research vessel on a remote river. While distracted by news of the Mars 2020 Perseverance rover (successful landing!), their vessel crashes and begins capsizing. After their initial panic, they are dismayed to find the collision has taken out their communications equipment.
In some quick thinking, Jack finds a printed log of ships expected to be nearby. Fortunately, there is a marine zoology expedition about a mile downriver, and our crew just needs to get an SOS out to that ship.
Initially, Jack tries simply yelling for help. Unfortunately, this doesn't do much good - and the explanation why requires some fluid mechanics.
I have received questions from clients using AFT Impulse where they ask something like "I closed this valve. Why is the maximum pressure spike way over there and not at the valve?" This comes from years of developing a "common sense" adapted to steady-state flow. With steady flow, a change between states of equilibrium has a local effect that...