1. Title of Dataset: PIV_experiments
Data were collected in Laboratory of Hydrodynamic Micromodels, Institute of Geophysics, Polish Academy of Sciences

2. Folder List: 

Folder Settling_experiments contains two sub-folders with data for each experimental set.

AS3_AS3XG1 - experiment with seawater layer (AS3) overlying a seawater (AS3) with dispersed xanthan gum;
AS3XG1_AS60 - experiment with seawater (AS3) sith dispersed xanthan gum overlying seawater layer;
where XG - xanthan gum, 1 indicates solution with concentration of 1 g/L, AS - artificial seawater, number indicates concentration of salts in g/L.

3. Additional related data collected that was not included in the current data package: 
Data on the rheological properties of solutions stored in Rheological_data folder.
	
4. Methodological information:

Experiments were performed in 50 cm x 8 cm 8 cm transparent tank filled with two-layered liquid 
seeded with fluorescent PMMA particles (1-20 μm). Temperature of liquid was 21 C deg (+- 1 C deg).
Solid particles individual particles as well as two particles (to observe interactions) were released below liquid surface to settle gravitationally.
A vertical laser sheet (green light, Nd:YAG double-pulsed laser) was aligned with the trajectory
of a falling sphere, which was in a sistance 3 cm from the front wall. 2D camera images (2448x2048 pixel, 124 Hz) were processed 
using Dantec Dynamic Studio and custom scripts in Matlab®. 
Adaptive PIV analysis was applied to compute instantaneous velocity vector fields, followed by Universal outlier detection and averageing filter. 


5. Data-specific information:
Each sub-folder contains folders reporting velocity field data from specific runs. Folders are named after type of particle in the following format:
nP_ind where P indicates the type of particle (S – sphere made of polyoxymethylene (density of 1.37 g/cm3), D – disk made of acrylonitrile butadiene styrene (density of 1.04 g/cm3) 
ind - indicates sphere diametrer in mm; n - indicates if dataset presents single-particle case or double-particle (interaction) case.
S_5,S_4, S_3 - spheres of diameters 5 mm, 4 mm, 3 mm, respectively
D - disk of diameter 3 mm and thickness of 0.3 mm


Velocity field data are stored in a sequence of csv files that indicate time instant and 
contain data on the position of particle centroid and 2D componensts of velocity field
in four columns: x [m], y [m], U[m/s], V[m/s]
where x - horizontal cooridnate, y - vertical coordinate, U - horizontal velocity, V - vertical velocity.