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SUPPLEMENTARY DATA: Pressure and shear flow singularities: fluid splitting and printing nip hydrodynamics
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Last modified: 2023-01-29 (yyyy-mm-dd)

This TUdatalib data set contains supplementary data for the following paper:

Pressure and shear flow singularities: fluid splitting and printing nip hydrodynamics
Matthias Elia Rieckmann (1), Pauline Brumm (2), Hans Martin Sauer (2), Edgar Doersam (2), Florian Kummer (1)
Physics of Fluids, 2023

(1) Technical University of Darmstadt, Department of Mechanical Engineering, Chair of Fluid Dynamics, 64287 Darmstadt, Germany
(2) Technical University of Darmstadt, Department of Mechanical Engineering, Institute of Printing Science and Technology (IDD), Magdalenenstr. 2, 64289 Darmstadt, Germany

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DATA SET DESCRIPTION

The data set consists of image data in form of 144 high-resolution scanned images of gravure printed finger patterns. The scan resolution is 2400 ppi. The image files are named according to their printing parameters.

Example:
010mmin_1_R060.tif

010mmin --> Printing speed of 10 m/min
1       --> Sample number 1 of 6
R060    --> Raster frequency of 60 lines/cm

All samples were printed on the gravure printing unit of the Gallus RCS 330-HD printing press in the IDD printing lab. The used electromechanically-engraved printing form has a tonal value of 100 % and a raster angle of 59.35°, which corresponds to HELL raster angle #2.

Note that samples with a raster frequency of 60 lines/cm at printing speeds of 60 and 75 m/min are erroneous due to smeared ink resulting from insufficient drying.

The printing direction goes from bottom to top in all images.

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METADATA

For all samples, finger distances in micrometers were determined using an averaged 1-dimensional fast Fourier transform (FFT) over all rows of the image. Finger frequency is 1/(finger distance).

The results of the FFT analysis can be found in the CSV-file 'finger_distances.csv', which is also part of this TUdatalib data set.