Practical demonstration and visualisation are essential elements of fluid flow study.
The S2 – Mobile Bed and Flow Visualisation Tanks are used in two principal fields of study. The first involves detailed investigation of mobile bed situations. These may be in relation to watercourses or civil engineering structures.
The second field involves two dimensional flow visualisation. This may be undertaken using the Ahlborn (c.1902) dust indicator technique or by any other suitable method of flow visualisation.
The tank is moulded from self coloured Oxford Blue (BS0105) glass fibre reinforced plastic with steel reinforcements to provide rigidity. It is manufactured in three sections; the inlet tank, the working section and the discharge reservoir tank. The sections are joined by flanged connections and despatched from the factory as a complete assembly. A drop-tight adjustable overshot weir with upstream sand trap is accommodated within the discharge tank. The inlet tank features a perforated baffle plate which spreads the flow evenly across the width of the table.
A removable glass sheet coloured blue on one side and white on the other, is provided to cover the sand bed when flow visualisation experiments are in progress. A pair of adjustable aluminium instrument rails are fitted to the top of the tank. These extend over the full length of the working section and one rail carries a positioning scale.
The depth gauge supplied is used to measure the water level and to map the contours of the sand bed produced during exercises.
It is provided with a stainless steel hook and point and incorporates a Vernier scale enabling levels to be determined accurately.
The gauge is designed for mounting on the instrument carrier assembly which can be positioned over any point of the working area. The main carrier (longitudinal traverse) is provided with a locking device and cursor to operate in conjunction with the instrument rail scale.
The sub-carriage (transverse traverse) operates on rails provided by the main carriage. There is again a transverse scale and locking device. The correct use of the apparatus is described in a comprehensive manual supplied with the tank.
Water flow is provided by a centrifugal pump made of materials which are selected for their corrosion resistance as is the pipework which includes an electrically operated flow regulating valve.
A GRP moulding carries the pump, control valve, rigid pipework and ‘in-line’ flowmeter.
The assembly is connected to the tank by flexible hoses. The motor starter and digital meter readout are mounted in a table top cabinet supplied complete with the required flexible cables.
The tank is available with optional working lengths:
Model S2-2M: working length 2m
Model S2-4M: working length 4m