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Axisymmetric body

This dataset contains the measurements on the Axisymmetric body (160mm diameter, elliptical nose cone, l/d = 5), collated for Loughborough University by Max Varney on 2020/06/15. More information about this dataset can be found in the paper “Three-dimensional structure of the unsteady wake of an axisymmetric body”, Physics of Fluids 31, 025113 (2019); https://doi.org/10.1063/1.5078379.

This Dataset is obtained from the Large Wind Tunnel at Loughborough University, which is a closed working section, fixed ground open return tunnel. The CAD geometry for the wind tunnel is included in the dataset as an ASCII .stl file, with the units in mm. The .stl file of the geometry and its mounting hardware is also provided, however, the yaw and pitch of the model were incrementally adjusted to produce an axisymmetric base pressure at each PIV plane and pressure measurement. As such the .stl file, as imported, will result in an asymmetric flow field.

For the purpose of ease of comparison with computational work, no corrections have been applied to this data. All data is presented in SI units and all measurements are from the origin of the model (on the base of the model, at the centre of the base) with x positive downstream and z positive up, using a right-hand rule to find positive y.

There are two datasets provided for this geometry.
DATASET #1 – 30m/s (Re_d=3.2×10^5)
Tomographic Particle Image Velocimetry
Base Pressures

Dataset #1 uses two sets of data appended to one another to generate a larger more statistically meaningful dataset. For the Tomographic Particle Image Velocimetry results, two experiments consisting of 250 uncorrelated vector fields (totalling 500 images) were used, taken at 7.26Hz. The base pressures use two sets of 90,000 samples (totalling 180,000 samples) taken at 300Hz (600 seconds total). There is no time correlation between the Tomographic and pressure results.

DATASET #2 – 40m/s (Re_d=4.3×10^5)
Planar (Y=0m, Z=0m and Z=0.04m) and Stereo (X=0.06m, X=0.12m, X=0.18m and X=0.24m) Particle Image Velocimetry
Base Pressures
Forces

Dataset #2 uses individual sets of data. Both the force and pressure measurements have 90,000 samples, taken at 300Hz (300 seconds total), these were taken at the same time (+/- 10 seconds) but are not correlated to one another. The vertical PIV at Y=0 m contains 1000 uncorrelated vector fields taken at 15Hz with all other planes containing 2000 uncorrelated vector fields.

For both datasets, a 300 second pressure measurement was taken to ensure the base pressure was close to axisymmetric prior to the Particle Image Velocimetry data being taken. The in-plane (planar) position of the Particle Image Velocimetry vectors are approximate, as they have been positioned manually.