Boundary conditions in fluid dynamics

Imagine you have a pool filled with water and you want to understand how the water is going to move when you jump into it. In order to do this, you need to set some rules, or "conditions", about what happens at the edges of the pool or at the surface of the water.

These rules are called "boundary conditions". They tell us how the water flows and behaves near the edges of the pool or near any other boundaries that may exist, like a wall or the bottom of the pool.

Boundary conditions are important in fluid dynamics because they help us create a mathematical model of how liquids behave. This mathematical model can help us predict how the liquid will move when certain conditions are changed, like when an object is dropped into the pool, or when the temperature changes.

One common boundary condition is called "free slip", which means that the liquid can slide smoothly over any boundary, like the sides of the pool. Another common boundary condition is called "no-slip", which means that the liquid sticks to the surface of any boundary, like the bottom of the pool.

Boundary conditions can also be used to describe the behavior of the liquid at the surface, like how waves can form when a wind blows over the surface of the water.

Overall, boundary conditions are important for understanding how liquids behave and for creating mathematical models that can help us make predictions about the future.