"I can't see any of my files in the import dialog...?"
When the import dialog is opened, it will automatically show files from the default directory/folder (specified through Configuration). Only files with the correct filename format will be shown.
If you want to import data files from a different directory, click on the "Choose Directory" button. This will open a selection dialog through which you can choose an alternative directory. You will not see any files in the selection dialog which appears - the dialog is to allow you to choose the directory (the clue's in the button name!). Once you have selected a directory, any files in the selected directory which have the appropriate filename format will be shown in the import dialog.
Is there a user guide?
Yes, here. It should be enough to get you started but it is incomplete - most functionality should be self-explanatory, try right-clicking on graphs and tables!
Suitability
This software was written to process 3-D velocity data gathered in an laboratory flume, and the terminology relects that. However, it can be used to process any time-series in an appropriate format (some of the parameters calculated from the time-series may not make much sense if the data is not velocity data though).
Notation
x - streamwise direction (into the screen)
y - lateral direction (positive from left to right)
z - direction normal to the channel bed (i.e. "vertical"; positive upwards)
u - instantaneous velocity in the x-direction; U is the mean of u over a time-series
v - instantaneous velocity in the y-direction; V is the mean of v over a time-series
w - instantaneous velocity in the z-direction; W is the mean of w over a time-series
Note: This is a left-handed coordinate system. Many instruments (e.g. Nortek Vectrino) use a right-handed system. In that case, ensure that the "Invert y-axis..." checkbox is selected in the configuration.
What file formats will the VSA read?
Nortek Vectrino+ v1.10
- Unconverted (*.vno) files
- Converted (*.dat) files
Nortek Vectrino II
- Matlab format (*.mat) files
- Converted (*.dat) files
Nortek Polysync v1.0.17
- Unconverted (*.vno) files
- Converted (*vel.txt) files
Nortek Vector
- Unconverted (*.vec) files (files recorded in "burst mode" are automatically split into bursts)
- Converted (*.dat) files
Turbulent Flow Instrumentation (TFI) Cobra Probes
- Unconverted (*.thX) files
3-D CSV data:
u(1),v(1),w(1) u(2),v(2),w(2) . . . . . . . . .u(n),v(n),w(n)
A file containing single U measurements, with their cross-sectional co-ordinates (y,z):
y(1),z(1),U(1) y(2),z(2),U(2) . . . . . . . . .y(n),z(n),U(n)
What filtering methods are available?
Exclude Level
Measurements which lie more than a specified factor of the standard deviation are excluded
Phase-Space Thresholding (PST)
See "GORING, D. G. & NIKORA, V. I. 2002. Despiking Acoustic Doppler Velocimeter Data. Journal of Hydraulic Engineering, 128 (1), 117-126."
Modified Phase-Space Thresholding (mPST)
See "PARSHEH, M., SOTIROPOULOS, F. & PORTE-AGEL, F. 2010. Estimation of Power Spectra of Acoustic-Doppler Velocimetry Data Contaminated with Intermittent Spikes. Journal of Hydraulic Engineering, 136 (6), 368-378."
Velocity Correlation
See "CEA, L., PUERTAS, J. & PENA, L. 2007. Velocity Measurements on Highly Turbulent Free Surface Flow Using ADV. Experiments in Fluids, 42 (3), 333-348."
Signal Correlation
Measurements for which the recorded correlation is less than a specified value are excluded (note that this is only available for data imported from unconverted Vectrino, Vectrino II and Polysync files (.vno))
50 Point Moving Average
The filtered value is the mean of the preceding 25 points, the point value and the following 24 points.
wDiff
Where two independent measurements of w are made, w1 and w2, a limiting difference between the two (as a percentage of the w1 standard deviation) may be specified and measurements for which the limit is exceeded are excluded.
What assumptions are made?
The fluid is water, and so where density is used in calculations the density of water is used - 1000kg/m3.
If other fluids are used, or density variation due to temperature is an issue, then the output can simply be scaled appropriately.
This software is released in the hope that it will be useful to other users of Nortek ADVs or other devices with compatible outputs. It is released under the terms of the GNU General Public License, version 3. Please follow the link for formal licencing information, but note that this software comes with no warranty (having said that, it is designed to only read from the original data files, not write to them, so your data should be safe!).
The work of the organisations linked to below has greatly aided the development of this software.
However, linking to them is in no way intended to imply their recommendation, collaboration with development or even knowledge of the existence of this software.
