Manual – Starflow QSD Model 6527B and 6537A
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 08 05 2023.docx
Page 38
6. INSTALLATION
6.1. 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 the 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, such as snow melt.
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 have little effect on the
measured velocity, but they 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 from 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 the 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.
