Dispersion Models

Tamar Estuary model

Shown here is the simulation of freshwater movement (or associated pollutant such as nitrate) down the Tamar estuary. The oscillation shows the effect of the tides and the changing colours indicate dilution:

• red (1-100) • blue (100-10,000) •yellow (10,000-1,000,000).

Note how material from the Tamar is washed into the Tavy and Lyner on subsequent tides. The whole simulation represents a period of 10 days. Simulated with the BELPLUME model, with data provided by Plymouth Marine Laboratory.

Hydrogen gas release

This display is a simulation of a hydrogen gas release inside a process building. The building is ventilated with inlets at ground level and extraction in the centre of the ceiling, however the buoyancy of the gas dominats initially with the cloud rising rapidly and spreading across the ceiling. The ventilation clears the hydrogen from the centre. Changing colours indicate dilution and areas of the gas cloud dissapear as the concentration is reduced to below the flammability limit. The whole process takes about 15 seconds.

Gravity Current in a Tank

This is a numerical simulation of a gravity current flow of salt water (• red) flowing under freshwater ( • blue). Note the Kelvin-Helmholtz billows that form on the back of the current as it advances along the bottom of the tank. Gravity currents are common in the environment, for example avalanches and salt flow in stratified estuaries.