A water tunnel is very similar to a wind tunnel except instead of using air inside the tunnel, water is used instead. It is an experimental facility that is used to experiment and test the hydrodynamics of underwater objects that are flowing through the water tunnel, as well as any objects that is placed within them. Although though not as advanced as today, some forms of water tunnels have been used by men for centuries. The importance of these tunnels have recently gained recognition and they are becoming more useful in many different ways, like improving ship construction.
Wind tunnels are able to provide experts with vast amounts of research capability, but there are times when the use of wind is not conducive to the type of material that will be experimented with. Often times, a water tunnel can be used instead because it is better able to perform three-dimensional experimentation. This is because the flow of water allows for a greater variety of visual procedures to be used, for example, food coloring can easily be traced through the water, as well as various other forms of dyes. These tunnels also provide better research for objects typically found in water like ships and marine life.
Water tunnels can vary greatly in size depending on the research it is intended for. How fast the flow of water is inside of it is an important variable in any research being done. The flow is directly controlled by pumps that will allow the water to flow at any speed, and to also be stopped when necessary. Unlike wind tunnels, water tunnels are unpressurized inside and make entry into it easier. This allows researchers to easily enter the testing section of the water tunnel and allows access to an environment in which to perform their research.
These tunnels also play an important role in ship construction. They are used to test how the propellers of different types of ships work. This type of water tunnel testing model is called a cavitation tunnel and is used to test for any fluctuation in pressure, built-up erosion and cavitation noise of different ships. The ability to control the water speed inside the tunnel allows for the experimentation of these propellers at different water speeds. This testing allows those involved in ship construction to be able to test different components of a ship before completing the finished product.