| EPSRC Reference: |
EP/D055539/1 |
| Title: |
Replacement plasma tube for laser and fan for wind tunnel |
| Principal Investigator: |
Simons, Professor RR |
| Other Investigators: |
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| Researcher Co-Investigators: |
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| Project Partners: |
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| Department: |
Civil Environmental and Geomatic Eng |
| Organisation: |
UCL |
| Scheme: |
Standard Research (Pre-FEC) |
| Starts: |
01 October 2005 |
Ends: |
30 September 2006 |
Value (£): |
20,007
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| EPSRC Research Topic Classifications: |
| Coastal & Waterway Engineering |
Multiphase Flow |
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| EPSRC Industrial Sector Classifications: |
| No relevance to Underpinning Sectors |
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| Related Grants: |
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| Panel History: |
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Summary on Grant Application Form |
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Laser Doppler velocimetry (LDV) is a technique for measuring flow velocities and turbulence by shining laser beams into a moving fluid. The method has the major advantage that it does not require any physical instrument to be placed into the flow and thereby disturb it. And because the measuring point where the laser beams cross is very small, it is possible to measure the changing velocity across highly sheared flows such as those within the boundary layer very close to a solid surface with great precision. The very rapid response achievable with the photo-sensor and electronic analysis system makes it an ideal instrument for measuring velocities in unsteady flows such as turbulent boundary layers and wave-type flows. The Fluids Group in the UCL Civil & Environmental Engineering Department specialises in experimental investigations into complex fluid flows, and LDV systems have been one of the standard techniques for measuring flow velocities and turbulence for many years. In 2001, the Group was funded by EPSRC (GR/R06878) to purchase a modern, state-of-the-art two-component fibre-optic LDV system to replace older instruments. The optical head, linked to the laser tube by a 20m optical fibre, was mounted on a trolley equipped with a programmable x-y-z traverse device. This made it possible to make LDV measurements in all flow facilities within the laboratory. The optical head could also be switched with a special lens to produce a laser light sheet suitable for particle image velocimetry (PIV) and flow visualization. Since its installation the LDV has been in almost continuous use, mainly for a study into the structure of the turbulent boundary layer over a slat-type rough boundary and its correlation with dye dispersion measurements, with particular application to the dispersion of pollution in urban environments but of relevance to all boundary layers over 2-d roughened surfaces. The LDV has also been used for measurements of wave-induced mass transport in a flume, flow in and above scour holes around model structures, and for associated visualization studies. The 5-watt plasma tube that powers the system was cooled by water from the laboratory's recirculation system. Unfortunately, this water is not purified, and salts gradually accumulated on the glass surface to the extent that, after 2000 hours of logged use, the plasma tube fractured.The purpose of this application is to request funds for the purchase of a replacement plasma tube. Funds are also sought to install a heat exchange system which the suppliers advise will isolate a reservoir of pure water in contact with the tube from the recirculating water and thereby increase the lifetime of the tube. Once in operation, the laser will be used for LDV and flow visualization of a wide range of continuing and new projects in the fields of coastal engineering, wind engineering, pollution dispersion, and turbulence.One of the main facilities in the Pat Kemp Fluids Laboratory is a wind tunnel. At present this is driven by a large fan which is of an old design that cannot be modified to allow its rotational speed to be changed in a controllable way. To overcome this, wind speed in the tunnel is varied in a coarse fashion by venting air through louvres between the fan and the test section of the tunnel. As a separate item in the proposal, it is requested that funds are made available to purchase a new fan and controller for this wind tunnel.
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Key Findings |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Potential use in non-academic contexts |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Impacts |
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| Description |
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk |
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Sectors submitted by the Researcher |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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