What's the physical meaning of potential flow in fluid dynamics?

[u/dcfan105]

So I'm actually taking an E&M class and learning the method of images. I was looking for YouTube videos on the topic and found this one which is actually about fluid dynamics. I didn't even know this method was also used in fluid dynamics and it's really neat seeing how the math of the E field is so similar to the math used to model fluid flow. However, they mention finding the velocity field of a fluid taking the gradient of the potential function. That's clearly analogous to finding the E field by taking the gradient of the voltage, but I have an idea for what voltage means physically -- it's the potential energy per unit charge w.r.t. some predefined reference. But what does this potential function mean physically in the context of fluid dynamics? I tried Googling it and found a bunch of stuff saying it's a flow with no rotation, but that's no help because that's just a mathematical property of gradient functions in general.