Manual – Starflow QSD Model 6527B and 6537A
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 17 01 2020.docx
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5.0 INSTALLATION
5.1 Site Considerations
The Doppler signal received, and the accuracy of the computed velocity, is related to the flow and
cross-section characteristics of the site. A suitable site has the following features:
Feature
Description
Flows are laminar and the velocity measured
by the transducer can be related to the mean
velocity of the channel.
Velocity is measured from a limited path in front
of and above the acoustic sensors. This area
varies with the amount of suspended material in
the water and the channel characteristics. The
user has to determine the relationship between
the measured and mean velocity.
The channel cross section is stable.
The relationship between water level and the
cross-sectional area is used as part of the flow
computation.
Velocities are greater than 20 mm / second.
The transducer does not process velocities
slower than this. The maximum velocity is 5
metres / second. The transducer will measure
velocities in both directions.
Reflectors are present in the water.
Generally the more material in the water the
better. Starflow QSD generally works well in
clean natural streams but problems may be
encountered in extremely clean water.
No excessive aeration.
Bubbles are good scatterers and occasional
small bubbles will enhance the signal. However
the speed of sound can be affected if there are
excessive amounts of air entrapped in the flow.
The bed is stable and Starflow QSD will not
be buried by deposits.
Some coating and partial burying has little effect
on the measured velocity but it should be
avoided. Any burying or sediment covering the
depth transducer will affect the depth reading
results.
Starflow QSD Pointing Upstream or
Downstream?
Pointing the sensor end downstream will stop it
accumulating debris; however in some channels
the sensor body may disturb the velocity
distribution unacceptably. The velocity reading
will be positive when pointing upstream and
negative when pointing downstream. The
Starflow QSD may be configured to only read
positive velocities regardless of water flow
direction.
Starflow QSD Depth sensor not situated
parallel to the surface?
If Depth sensor is not parallel to the surface (~
±10 °) the readings could be compromised
Corrugated Pipes
In general the Starflow QSD is not suited to
installation in corrugated pipes.
