A powerful method of demonstrating potential fl ow in fl uid dynamics
• Visually eff ective demonstration of a wide variety of fl ow patterns around diff erent shapes
• Ideal for individual as well as group work and classroom demonstrations
• Compact and free-standing
• Models easily cut from sheet (included) – almost any shape possible
• Ideal introduction to incompressible potential fl ow (aerodynamics)
• Source and sink points provided
• Can show soil seepage problems
Description
TecQuipment’s Hele-Shaw apparatus produces streamlines in a laminar, steady fl ow. It allows students to study various source and sink arrangements, and look at fl ow around an unlimited variety of diff erent shaped models. The apparatus can represent water seepage through solids, and can simulate any process satisfying the Laplace equation in two dimensions. Thus lecturers can also use it to represent fl ow in other branches of engineering, such as aerodynamics or electricity and heat flow.
The apparatus works with a steady, air-free water supply and suitable drain. The equipment consists of a channel formed between two plates. Water fl ows along the channel at a low Reynolds number, so the inertia forces are not important.
A dye fl owing through several small holes at the upstream end produces streamlines. The removable top glass plate has gridlines to help analysis of the fl ow patterns. The apparatus comes with a rubber sheet from which to cut out various shapes of models. When placed between the two plates, students can see the streamline patterns fl owing around the models. Also, valves and a vacuum pump allow students to connect two sources and two sinks (or any combination of both).
To perform experiments, students start the water fl ow and open a dye valve just enough to produce easily visible streamlines. They then use valves to allow water to fl ow from a source point or drain into a sink point, or various combinations of fl ow or sink points. The vacuum pump strengthens the sink points.
To incorporate models into the free stream of the apparatus and study the eff ect on streamlines, students cut the shapes they need from the rubber sheet (supplied). They then sandwich the model between the two plates of the apparatus and start the flow.
To provide a constant head and smooth, air-free fl ow from your water supply, TecQuipment off ers the optional Header Tank (H9a).
Recommended Ancillaries
• Header Tank (H9a) – A wall-mounting tank with a fl oat valve, overfl ow and a fl ow control valve and pipework.
Learning Outcomes
Various fl ow visualisation experiments in two dimensions, including sink and source points and fl ow around models, for example:
• Sources and sinks in a uniform stream
• Doublet in a uniform stream
• Flow around a cylinder (disc) and an aerofoil
• Flow through an orifi ce and a diff user
• Flow through a heat exchanger
• The momentum equation
• Laminar fl ow relationship for fl ow between two parallel plates
• Mean velocity equations (including seepage in soils)
• Potential fl ow relationships
Essential Services
• Clean, air-free water at 1 litre per minute at constant pressure between 1.5 and 2.5 metres head. This can be supplied by the Header Tank (H9a, available separately).
• A suitable drain
