Planetary core-style rotating convective flows in paraboloidal laboratory experiments
Data files
Oct 04, 2022 version files 10.41 GB
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Data.zip
10.41 GB
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README.txt
1.84 KB
Abstract
Turbulent convection in a planet’s outer core is simulated here using a thermally-driven free surface paraboloidal laboratory annulus. We show that the rapidly rotating convection dynamics in free-surface paraboloidal annuli are similar to those in planetary spherical shell geometries. Three experimental cases are carried out, respectively, at 35 revolutions per minute (rpm), 50 rpm and 60 rpm.Thermal Rossby waves are detected in full disk thermographic images of the fluid’s free surface. Ultrasonic flow velocity measurements reveal the presence of multiple azimuthal (zonal) jets, with successively more jets forming in higher rotation rate cases. The jets’ cylindrical radial extent is well approximated by the Rhines scale. Over time, the zonal jets migrate to larger radial position with migration rates in good agreement with prior theoretical estimates. Our results suggest that planetary core rotating convection will be comprised of flow structures found in other turbulent geophysical fluid dynamical systems: convective turbulence dominates the small-scale flow field, and also act to flux energy into larger-scale, slowly evolving zonal flow structures. How the ambient magnetic fields in planetary core settings affect such turbulent flows remains an open question.
Raw data is provided for the three cases mentioned in the paper: 35, 50, and 60 RPM. Additionally, calibration data is provided to remove offsets in the IR readings with respect to the thermistors. In these cases, the thermistors reading in Celsius to match to the IR readings was 24.6367, 26.2664, and 24.3968.
The “ascii” and “irb” folders contain the same information in different file formats. The ascii files are matrices of the temperature in Celsius per pixel. The .irb files are the files taken from the InfraTec software and can be re-opened if using the same instrument. The 50 and 60 RPM cases have folders under ascii titled “Full” which just contains the same data as the time-stamped folders but in one folder for ease of importing.
The “dop” folder contains binary data files with the data taken from the UDV. MATLAB and python routines for reading these files can be found through the Signal Processing website: https://www.signal-processing.com/download.php
The thermistor readings from the bottom of the tank can be found in the “thermistor” folder in a variety of formats. I recommend looking at the “_working” .mat files as some of the thermistors broke throughout testing, so these files contain data from all the functioning thermistors at the time of data collection. Azimuthal thermistors are thermistors that had intended to be placed along the outer wall of the tank. Lateral thermistors are those that crossed the annulus of the tank radially. The ‘_all’ .mat file thermistors contains all the available thermistors (both working and broken). The PNG files show the lateral thermistors over the time of the experimental run (broken into 4 ten-minute segments).
NOTE: Files were compressed on a Windows platform. As a result, Mac/Linux users may need to install a third-party decompression software to properly unzip the files.