Dataset requirements for shear probes: Difference between revisions

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This section provides an overview of the NetCDF format of benchmark dataset for instruments that measure microstructure shear.
This section provides an overview of the NetCDF format of benchmark dataset for instruments that measure microstructure shear.
=== Raw timeseries ===
<div class="mw-collapsible mw-collapsed" id="raw" data-collapsetext="Collapse" data-expandtext="Expand Raw">
===Dimensions===
'''Example of collapsible list'''
<ul class="mw-collapsible">
  <li>TIME</li>
  <li>HEIGHT_AS</li>
</ul>
'''Example of collapsible table'''
{| class="wikitable sortable mw-collapsible"
! Short name
! Standard name
|-
| TIME
| days since 1950-01-01 00:00:00 UTC
|-
|n_shear_sensors
|number of shear channel
|-
|}
{| class="wikitable sortable mw-collapsible"
|+ These dimensions are defined for the raw group level but have a caption.
! Short name
! Standard name
|-
| Content
| Goes
|-
| In Here
| Please
|}
===Required Variables===
{| class="wikitable sortable"
|-
! Parameter Name !! Standard Name !! Units of measurement !! dimension
|-
| PRES || sea_water_pressure<br /> water_pressure || dbar || TIME || 1,2
|-
| TIME || time || days since 1950-01-01 00:00:00 UTC || TIME || 1
|-
| SHEAR || water_velocity_shear || s-1 || [TIME, n_shear_sensors] || 1
|}
===Optional Variables===
{| class="wikitable sortable"
|-
! Parameter Name !! Standard Name !! Units of measurement !! dimension
|-
| VIB || platform_vibration || NA || [TIME, n_vibration_sensors]
|-
| ACC || platform_acceleration || m s-2 || [TIME, n_acc_sensors]
|-
| TEMP || sea_water_temperature<br /> (water_temperature) || degree_Celsius || [TIME,n_T_sensors]
|-
| CNCD || sea_water_electrical_conductivity<br /> (water_electrical_conductivity) || S m-1 || [TIME_FAST,n_C_sensors]
|-
| GRADT || temperature_gradient ||  || [TIME, n_gradT_sensors]
|-
| GRADC || conductivity_gradient || || [TIME, n_gradC_sensors]
|-
| PITCH || platform_pitch_angle || degree || [TIME]
|-
| ROLL || platform_roll_angle || degree || [TIME]
|}
===Group Attributes (metadata)===
<div class="mw-collapsible"  id="raw_att"  data-expandtext="Expand Raw Attributes" data-collapsetext="Collapse attributes">
=Required=
<ul>
  <li>Att 1</li>
  <li>Att2</li>
</ul>
=Optional =
<ul>
<li>Enter here</li>
</ul>
</div>
</div>
===Quality-controlled and segmented timeseries===
<div class="mw-collapsible mw-collapsed" id="segmented" data-collapsetext="Collapse" data-expandtext="Expand QAQC timeseries">
Insert info here in the same format as [[#raw|Raw]]
</div>
===Spectra===
<div class="mw-collapsible mw-collapsed" id="spectra" data-collapsetext="Collapse" data-expandtext="Expand Spectra">
</div>
===Dissipation===
<div class="mw-collapsible mw-collapsed" id="dissipation" data-collapsetext="Collapse" data-expandtext="Expand Dissipation">
</div>
</div>




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return to [[Shear probes]]
return to [[Shear probes]]

Revision as of 01:08, 9 November 2021

This page provides an overview of the NetCDF format of benchmark dataset for instruments that measure microstructure shear using airfoil probes.

  • The absolute minimum signals and information required to estimate the rate of dissipation of kinetic energy consists of:
  • a sampled shear-probe signal,
  • a means of determining the speed of flow past the shear probe, and
  • a means to estimate the temperature of the fluid so that you can determine its kinematic viscosity.

The sampling rate of the shear-probe signal should exceed significantly (by a factor of 2 to 4) the value of 150U, where U is the speed of the flow past the shear-probe. This speed is often called the speed of profiling, even when the probe is fixed in space and the current causes fluid to flow past the shear probe. The value of 150 cpm equals the spatial resolution of the commonly used shear probe.


  • The desirable data set

A far more desirable, but not absolutely necessary, set of data consists of the following.

  • Two or more shear probes for measurement redundancy.
  • Vibration sensors or accelerometers that are sensitive to the directions of sensitivity of the shear probes.
  • An accurate thermometer.
  • A pressure transducer.
  • A signal that can be used to estimate the speed of flow past the shear probe.
  • Pitch and roll sensors.

Most commonly available instruments carry two shear probes that are frequently oriented so that they measure orthogonal components of the shear and, thus, provide two independent estimates of the rate of dissipation that you should agree statistically.


Benchmark datasets: Shear probe measurements

ATOMIX provides several benchmark datasets consisting of four processing levels.

  1. Raw timeseries
    • full resolution data in physical units
  2. Quality-controlled and segmented timeseries
    • full resolution cleaned and despiked parameters from level 1, subdivided in individual sections.
  3. Spectra
    • raw and cleaned spectra
  4. Dissipation [math]\displaystyle{ \varepsilon }[/math] estimates
    • dissipation estimates and corresponding quality parameter as time series

return to Shear probes



Recommended data format

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