ELI5: Explain Like I'm 5

Smoothed-particle hydrodynamics

Smoothed-particle hydrodynamics, or SPH in short, is a way to approximate and study the behavior of fluids like water, air, or even lava. Imagine if you had a lot of tiny little balls or particles that represent bits of water, oil, or even sand. We can move these particles around and make them interact with each other so that we can see how they behave in different situations.

SPH gets its name from the way these particles move and interact with each other. Smoothed means that we smooth out the surface of each tiny little ball so that it is not a sharp corner, this makes mathematical calculations easier. Particles means just that, each tiny little ball is a particle, Hydrodynamics means the study of fluids.

Each particle represents a tiny bit of fluid, and we use math to figure out how the particle should move and interact with other particles around it. If a particle is close to another particle, it will start to have an effect on its movement, like a water molecule in a river, when one moves another is affected, we use equations to model these interactions between particles. As we add more particles, we can see how they flow and how they react to different forces.

Scientists and engineers use SPH to study how fluids move in different situations, such as the flow of water around a ship, or how oil spills move in the ocean, or even how lava flows from a volcano. They can also use SPH to simulate the effect of an object moving through a fluid; for example, how a rocket moves as it blasts off into space.

SPH has many applications and uses in various fields like engineering, computer graphics, and even gaming. Although it involves some complicated math, we can use our imagination to think of it as a bunch of tiny little balls of fluid that interact with each other.