Remote fluid velocity sensor

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jakes1487
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Remote fluid velocity sensor

Postby jakes1487 » Mon Jun 18, 2012 3:53 am UTC

Does anyone know if this exists or would be possible to build with any current means?

An apparatus located at a certain place that can measure the velocity (vector) of the surrounding fluid at any arbitrary point (or a large grid of fixed points) around it, within a certain distance. It cannot just measure the velocity at one point and extrapolate, because the fluid will be in some moving, chaotic state. It needs to be able to work on at least air and water.

Is there any way this might be possible?

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jmorgan3
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Re: Remote fluid velocity sensor

Postby jmorgan3 » Mon Jun 18, 2012 9:11 am UTC

jakes1487 wrote:Does anyone know if this exists or would be possible to build with any current means?

An apparatus located at a certain place that can measure the velocity (vector) of the surrounding fluid at any arbitrary point (or a large grid of fixed points) around it, within a certain distance. It cannot just measure the velocity at one point and extrapolate, because the fluid will be in some moving, chaotic state. It needs to be able to work on at least air and water.

Is there any way this might be possible?

Sounds like you want PIV. It requires seeding particles, and can be a bitch to get working properly. Can you tell us more about the exact flow situation and what you are going to use the information for?
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idobox
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Re: Remote fluid velocity sensor

Postby idobox » Mon Jun 18, 2012 10:02 am UTC

Doppler ultrasound measure the velocity of your blood from a distance.
Obviously this technology can measure only radial velocity, and I am not sure how well it would fare in fluid only.
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jakes1487
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Re: Remote fluid velocity sensor

Postby jakes1487 » Mon Jun 18, 2012 1:03 pm UTC

jmorgan3 wrote:Sounds like you want PIV. It requires seeding particles, and can be a bitch to get working properly.

It needs to measure air and water outside in the field, so there's no possibility of preparing the medium in any way.

Thank you for the link, though; looking around a little I was heartened by this sentence in the article on Laser Doppler velocimetry: "This distance restriction has recently been at least partially overcome with a new sensor that is range independent." [citation to article: Moir, Christopher I: "Miniature laser doppler velocimetry systems," SPIE Conference Proceedings, Optical Systems, 2009, vol. 7356]

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Re: Remote fluid velocity sensor

Postby Sizik » Mon Jun 18, 2012 3:25 pm UTC

A lot of small turbines.
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Re: Remote fluid velocity sensor

Postby jmorgan3 » Tue Jun 19, 2012 6:47 pm UTC

jakes1487 wrote:
jmorgan3 wrote:Sounds like you want PIV. It requires seeding particles, and can be a bitch to get working properly.

It needs to measure air and water outside in the field, so there's no possibility of preparing the medium in any way.

Thank you for the link, though; looking around a little I was heartened by this sentence in the article on Laser Doppler velocimetry: "This distance restriction has recently been at least partially overcome with a new sensor that is range independent." [citation to article: Moir, Christopher I: "Miniature laser doppler velocimetry systems," SPIE Conference Proceedings, Optical Systems, 2009, vol. 7356]


LDV still requires seeding particles. Water in the field might be dirty enough for it to work, but I doubt air will be. Also, LDV only gives data at one point, at random intervals.

Check out this paper using PIV underwater.

Again, what are you going to use this data for? Does it need to be time-resolved, or do you want averages? Do you need data over the whole domain simultaneously?
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jakes1487
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Re: Remote fluid velocity sensor

Postby jakes1487 » Wed Jun 20, 2012 12:49 pm UTC

jmorgan3 wrote:LDV still requires seeding particles.

Oh. :/

jmorgan3 wrote:Again, what are you going to use this data for? Does it need to be time-resolved, or do you want averages? Do you need data over the whole domain simultaneously?

The idea is to capture the state of a large volume of fluid at one time, integrate it forward in time to see how it will be in the next few seconds, and correct that as it goes with new measurements--sort of like predicting the weather. Of course, measurement of the "whole volume" will likely be accomplished by very rapidly measuring the velocity at a number of different points within it.


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