Fantastic Fluid Flow

Take a beaker of water and a beaker of golden syrup and turn them upside down. Aside from making an enormous mess, you will notice that very different things are happening to each one. The water empties quickly in an almighty splash, whereas the heavier, stickier golden syrup slowly pours out in a stringy puddle.

To explain this behaviour, we need to look at fluid flow. A ‘fluid’, is generally a word used to describe a liquid, but it in fact describes everything that flows, be it liquid, gas, or even some varieties of solid. Unlike firm solids, they cannot support stress and thus deform under pressure.

The way a fluid flows and depends on what it is made of, and this is very important to understand. It is very important to understand different types of fluid flow. For instance, when building a plane, the engineer needs to know exactly how the surrounding air will interact with the vehicle.

Vehicle designers also put a lot of attention into ‘streamlining’ their products. This means shaping them in such a way as to minimise air resistance, allowing air to travel smoothly over them as they travel through it, with as little turbulence (unstable, chaotic flow) as possible.