Brief Description
=================

2D PIV velocity field data from the open plume experiment run 2015 at the 
Forschungszentrum Juelich. An electrically heated copper block placed in an enclosure 
creates a buoyancy driven plume. 

Experimental Setup
==================

Camera System
-------------
-- two cameras are attached to each other, each having an own field of view (fov); 
   therefore two shifted images are captured, that overlap in the intermediate region 
   (fov1+fov2 and fov3+fov4 are captured simultaneously) 

-- both cameras are vertically moved to capture the full plume

-- each experimental run was traversed by the cameras twice, i.e. from bottom to top 
   and back

-- the naming for the field of views is as follows:
 - fov1a: lower camera, cameras at lowest position (no offset), traversal from bottom 
          to top
 - fov2a: same as fov1a, but upper camera
 - fov3a: lower camera, cameras at middle position (200 mm vertical offset), traversal 
          from bottom to top
 - fov4a: same as fov3a, but upper camera
 - fov5a: lower camera, cameras at highest position (355 mm vertical offset), traversal 
          from top to bottom
 - fov[12345]b: same as fov[12345]a, but for reverse traversal, i.e. from top to bottom

Experimental Outline
--------------------

ID : identifier for a data set
P  : electric power supplied to the copper block [W]
FF : frequency at which PIV measurements are taken [Hz]
NF : number of captured frames
LBN: original experiment name (for internal reference) 

ID			P		FF	NF		LBN
----------------------------------------
exp_30_1	29.8	10	100		Mess01
exp_30_2	29.8	10	100		Mess08
exp_30_3	29.8	1	117		Mess02_d
	
exp_56_1	55.6	10	100		Mess03
exp_56_2	55.6	10	100		Mess09
exp_56_3	55.6	1	180		Mess04_d
	
exp_78_1	78.3	10	100		Mess05
exp_78_2	78.3	10	100		Mess10
exp_78_3	78.3	1	180		Mess06_d
	
exp_96_1	96.0	10	100		Mess07
exp_96_2	96.0	10	100		Mess11
exp_96_3	96.0	1	180		Mess08_d

Data File Format
================

This data repository contains the processed velocity field data captured by the PIV 
system (SpitLight PIV Compact 400 by InnoLas).

Processed Velocity Fields
-------------------------

-- each data files contain the velocity information captured by a single field of view,
   see naming above
   
-- there are two types of files: 
 - frameXXXXX.dat: instantaneous velocity data for frame XXXXX
 - mean.dat: mean velocities and standard deviations (w.r.t. all captured frames of the 
   fov)
 
-- all data files are simple text files with UTF-8 encoding and Unix line endings

-- comment line start with a '#'

-- data values are separated by spaces and the decimal mark is a dot '.'

-- the files are organised as a table, where each row corresponds to an interrogation cell 
   and the columns are used as follows for the 'mean.dat':
 - column 1: x-coordinate of the interrogation cell
 - column 2: z-coordinate of the interrogation cell (vertical camera offset is considered)
 - column 3: temporal mean (all frames) of x-component of the velocity
 - column 4: temporal mean (all frames) of z-component of the velocity
 - column 5: temporal standard deviation (all frames) of x-component of the velocity
 - column 6: temporal standard deviation (all frames) of z-component of the velocity

-- the 'frameXXXXX.dat' files are organised as the 'mean.dat', but with following columns:
 - column 1: x-coordinate of the interrogation cell
 - column 2: z-coordinate of the interrogation cell (vertical camera offset is considered)
 - column 3: instantaneous x-velocity values at frame XXXXX 
 - column 4: instantaneous z-velocity values at frame XXXXX 

Example Script to Read and Visualise the Datasets
=================================================

A short Python script, named plot_fov.py is provided to demonstrate a simple way to read
the experimental data and plot vector fields. It is assumed to be run in the command line
and it takes data files as arguments. Additional options and the usage are displayed when
run with the '-h' option.