Water tunnel (hydrodynamic)

A water tunnel (or hydrodynamic tunnel) is like a big tube filled with water. Scientists use these tunnels to help them study how things move through water. The scientists put models of things into the tubes, like cars or boats. Then, they use the tunnel to measure water flow around and through the model. They can also measure the forces like drag and pressure on the model. This helps scientists understand why things move the way they do in water.