A water tunnel is a specialized facility used to study the behavior of water flow and the effects of various forces on objects submerged in water. These tunnels allow researchers to simulate real-world conditions, making it easier to analyze fluid dynamics, which is essential in fields like engineering and environmental science. In a water tunnel, water is circulated through a controlled environment, enabling scientists to observe how different shapes and materials interact with the flow. This technology is often used in the design of vehicles, such as boats and submarines, as well as in the study of aquatic ecosystems.