Simultaneous measurement with two Qliners in Oslo
On September 16, 2004 Qmetrix and Nortek organized a two day training seminar in Oslo. Part of the successful seminar was a measurement with two Qliners at Mjondalen Bru.
The river Mjondalen is 220m wide and up to 10m deep. The flow is dominated by tidal currents. The measurements were made from a 10m high bridge.
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Figure 1: View from the bridge on the two Qliners measuring in the neighbourhood of one of the bridge piles
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Figure 2: Figure 2: Participants in the seminar performing simultaneous measurements |
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The measured discharge is 54.2 m3/s ( +/- 1.0 m3/s), Fig 3. This result is obtained in 11 minutes.
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Figure 3: Discharge record from NVE using a calibrated Nortek EasyQ at the same site. The Qliner measurements were performed between 10.15 and 11.15 hours.
The first Qliner measurement resulted in a discharge of 247 m3/s.
The other Qliner measurement resulted in a discharge of 257 m3/s.
The Qliner review programme was used to inspect results in detail. The lower right graph shows the bathymetric profile. The three bridge piles are clearly shown as shallow areas. The blue line shows the position of the measurement at a position detailed in the right part of the window. Other graphs on the left side show (top to bottom)
- Flow speed in m/s as a function of distance along the bridge
- Specific discharge in m2/s as a function of distance along the bridge
- Discharge m3/s per measured segment
- Bottom depth in m as a function of distance along the bridge including the width of each segment.
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The site is interesting because of its depth and width.
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