Fine gas bubbles are perfectly suited to visualising flow fields. Due to reynolds scaling, many flow processes that occur in air can also be demonstrated by experiments in water.
The experimental unit can be used to visualise laminar and turbulent flow processes in a water channel. Hydrogen bubbles are generated electrolytically at a cathode made of thin platinum wire. A stainless steel plate is used as an anode. Small bubbles that detach from the platinum wire are easily carried along by the flow due to their small size.
An interchangeable model is used in the shallow water channel and flow travels around and through it. White led illumination is located along the experimental section on the walls of the water channel. The indirect illumination results in a high-contrast image.
Learning objectives and experiments
- Visualisation of two-dimensional flows
- Streamline course in flow around and through models
- Flow separation
- Vortex formation, demonstration of karman vortices
- Qualitative observation of the velocity distribution in laminar and turbulent flow
- Analogy to air flow
Features
- Visualisation of flow fields and streamlines by using electrolytically generated hydrogen bubbles
- Illuminated experimental section
- Different models: drag bodies and changes in cross-section
- Investigations in laminar and turbulent flow
Specification
- Visualisation of flow fields by using electrolytically generated hydrogen bubbles
- Platinum wire as cathode and stainless steel plate as anode for electrolysis
- Shallow water channel fitted with indirect led illumination along the experimental section
- Various models are included: aerofoil, rectangle, straight plate, curved plate, cylinder (various sizes), various models for changes in cross-section
- Flow straightener and glass spheres ensure consistent and low-turbulence flow
- Different flow velocities via variable-speed circulating pump
- Setting power (with display), pulse and pause duration of the power and the flow velocity in the water channel
Technical specification
- Pump with adjustable speed
- Max. Flow rate: 20l/min
- Bubble generator
- Current: 0…200ma
- Pause: 8,4…1800ms
- Pulse: 8,4…1800ms
- 3 cathodes with platinum wire
- Ø 0,2mm
- Length 30, 50, 75mm
- Anode, stainless steel plate, l-shaped
- Water channel: approx. 6l
- Experimental section: lxwxh: 550x150x50mm
- Illumination: white leds on the side walls of the water channel
- 230v, 50hz, 1 phase
- 230v, 60hz, 1 phase; 120v, 60hz, 1 phase
