Differences between ADCP and ADV measurements?

Geplaatst door Pete Bachant op March 14. 2011

Hi there,

I was wondering if anyone had experience with the differences between measuring flows with ADCPs versus ADVs. Are there discrepancies between the two for certain types of flow?

Re: Differences between ADCP and ADV measurements?

Geplaatst door P.J. Rusello op March 15. 2011

Hi Pete,

This is a fairly general question. Do you have something specific you're going to be looking at?

In general, there are numerous differences between the two types of instruments. ADCPs provide a velocity profile, use a diverging beam pattern, are monostatic and typically sample a larger spatial region for velocity estimates. Acoustic Doppler velocimeters are point measurement systems, use a converging beam pattern, are bistatic, and sample a small volume of water. These differences lead to strengths and weaknesses in depending on the measurement goal.

P.J.

Re: Differences between ADCP and ADV measurements?

Geplaatst door Jonas Røstad op March 15. 2011

Hi Pete,

Please also have a look at http://www.nortek-as.com/en/products for description of our products in the different categories.

Best regards

Jonas Røstad

Re: Differences between ADCP and ADV measurements?

Geplaatst door Pete Bachant op March 15. 2011

Thanks guys,

More specifically, I'm contemplating some quick measurements in a tow tank to compare results obtained with an Aquadopp versus a Vectrino. Velocity will be uniform, so measurements should be equal on average, but I was maybe hoping to get an estimate for how the measurements will differ.

Re: Differences between ADCP and ADV measurements?

Geplaatst door P.J. Rusello op March 15. 2011

The Vectrino will have fairly minimal flow disturbance during the tow depending on how it is mounted. You should recover the tow velocity easily although seeding will be an issue. Please check the Bibliography (http://www.nortek-as.com/en/knowledge-center/bibliography) for the Snyder and Castro paper and Improvements in Acoustic Doppler Velocimetry which address measurement in low scatter environments.

The Aquadopp has a larger form factor than the Vectrino, utilizes different processing and is also available in several different models/configurations. Depending on the processing used to determine velocity, noise will either be comparable to or higher than the Vectrino. Depending on where the sample volume is located you might also see the instrument wake. I would expect it to perform better in a low scatter environment, but this will depend on the specific model used to some extent.

Overall though, I would expect the measurements to work out fine if you are interested in mean velocities only.

P.J.

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Differences between ADCP and ADV measurements?