Despiking ADV data for irregular wave motionUp to Velocimeters - single point
Despiking ADV data for irregular wave motionPosted by Michele Bendoni at January 18. 2012
my name's michele. I collected data in a laboratory flume using Vectrino II.
In the flume was reproduced an irregular wave motion (significant wave height = 10 cm, significant period = 1.4 s) and velocity field was measured at different locations.
Data COR and SNR are respectively about 90 and 60, but sometimes velocity data present several spikes despite good COR and SNR values.
I'd like to use WinADV to detect and replace spikes but I wonder if the software could work well with unsteady velocity data (I'm not sure because I think that algorithm proposed by Nikora and Goring (2002) are suitable for steady flow).
However, I processed data using high pass filter (with matlab) in order to remove the sinusoidal component due to wave motion.
I obtained a .dat file that I can't process usign WinADV.
Is there any software for converting .dat file to .adv file ? (if it's possible).
If not, I can try to implement on matlab a despiking algorithm but what kind of despiking method is suitable for such data ?
Re: Despiking ADV data for irregular wave motionPosted by P.J. Rusello at January 18. 2012
I don't think WinADV will work for Vectrino II data. Fundamentally there's no reason it won't since the data is just a bunch of stacked Vectrino time series (in effect). However, I don't think WinADV can read the *.ntk Vectrino II binary format. I would contact the author of WinADV for support on this as it's not a Nortek product.
I would actually recommend taking a looking at the following paper: http://journals.ametsoc.org/doi/pdf/10.1175/1520-0426(2001)018%3C1540%3ATDEONB%3E2.0.CO%3B2
This method will give you a decomposed fluctuating velocity which you could then use a despising method such as Nikora and Goring on if you'd like. I think you will need to tweak things a bit depending on how well the periodic component is removed.
Re: Despiking ADV data for irregular wave motionPosted by Michele Bendoni at January 18. 2012
Sorry, I was wrong, it is Vectrino (not Vectrino II). Among the output files are *.adv and *.vno.
WinADV software reads .adv files.
However thank you for the paper.
Re: Despiking ADV data for irregular wave motionPosted by Mike Jesson at February 22. 2012
I've implemented a number of despiking algorithms as part of software developed for my PhD, which may be of some use to you (see thread Polysync (and Vectrino) Data Analysis Software). References for all algorithms used are included in the software and the user guide.