Water tanks

The Fluid Lab has a range of water tanks for conducting experiments on various research projects. Most of these tanks are made of transparent Perspex sheets of varying thickness with copper plates as heating or cooling surfaces. The transparent surfaces allow light to pass through so that flow visualization experiments can be carried out.

• Rectangular and square tanks

Typical tanks in this group have two copper plates on two opposing surfaces, and the rest of the surfaces are made of Perspex sheets. Heating and/or cooling chambers are attached to the model tank through the copper plates. An example of this type of tanks is shown in Figure 1 below.

These tanks are designed primarily for conducting vertical natural convection boundary layer and heat transfer experiments. Both transient and steady state experiments can be carried out with these tanks. The particular tank shown in Figure 1 is 1-m long, 0.24-m high, and 0.5-m wide. It also has two pneumatically-operated gates, one on each side, for start-up experiments. For the start-up experiments, the gates are initially at their resting positions so that the hot and cold water in the buffer tanks is separated from the copper plates (sidewalls) by air gaps. At the start-up, the gates are lifted up (Figure 2) within a fraction of a second so that the hot and cold water in the buffer tanks flushes against the respective sidewalls to initiate heating and cooling. An approximately instantaneous start-up can be achieved with this setup.

The smaller versions of rectangular/square tanks can be easily rotated for conducting other experiments such as Rayleigh-Benard experiments (heating from the bottom and cooling from the top) and pure conduction experiments (heating from the top and cooling from the bottom).

• Triangular and wedge-shaped tanks

These tanks are designed for modelling natural convection induced circulation in coastal waters. There are two typical configurations of these tanks, one with a sloping bottom and either free or rigid surface, and the other with a sloping bottom connected with a flat bottom, and again with either free or rigid surface. Schematics of these two configurations are shown in Figure 3.

The scale of these tanks goes from 300 mm up to 2 m in length. With the free surface configuration, lighting can be applied from the top to model radiative heating of the water body. The rigid surface configuration has a copper plate on the top surface, and is designed for temperature controlled heating and cooling experiments, in which hot or cold water is circulated through the chamber sitting above the rigid surface.