Public Lab Research note


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Analyzing wind flow and turbulence over a local agriculture field

by Ecta64 |

Intro

This was an attempt to try and develop a procedure for documenting the wind vector and turbulence in a column of air using the TALA kite anemometer kite.

I have documented the use of streamers on this kite before: https://publiclab.org/notes/Ecta64/11-28-2016/setup-for-photographically-monitoring-wind-vector-and-turbulence-with-a-kite but I did not attempt to try and monitor an entire column of air to a certain height using proper means to document vector and turbulence at each level.

Application

Living near agricultural fields means that I care a great deal about the chemicals sprayed near my home. By analyzing the local wind characteristics it is possible over time to develop a good idea of how the air flows and therefore how pesticide spray might travel or be affected by local conditions.

Setup and use

Markers consisting of small 3 inch loops of extra kite line were larks head(ed) onto the kite line at 10 meter intervals. Since the kite averages about 50-55 degrees inclination good approximate (kites are not totally still and some variation in altitude is unavoidable) heights can be determined. A 10 meter long streamer was added 5 meters below the kite. As each altitude marker of note was reeled out a photo and a compass reading were recorded (and for the compass later reversed to provide true wind vector). Multiple photos or readings can provide more accuracy as time permits.

Note: Since only one streamer is used (which greatly simplifies handling and recording) time will march on as each altitude is documented.

A easy way to image the kite and streamer is to align the lens of the camera with the angle of the line. This can confuse focus as with my first set of images but the results are still usable.

Results

Reading 1) Height: 12m, Direction: 287 degrees, Curling indicating turbulence visible IMG_3716.JPG

Reading 2) Height: 21m, Direction: 325 degrees, Less curling IMG_3730.JPG

Reading 3) Height: 29m, Direction:324 degrees, stable air = minimal curling IMG_3739.JPG

These images show a snapshot of wind vector and behavior from approximately 12-29 meters (+ - 3 meters). Higher altitudes were not obtainable due to site restrictions (tree line limiting downwind safety of the kite). Significant variation in vector and turbulence from between lower and higher altitudes is expected. Kite movements were sometimes suddenly erratic but settled out to readings above before measurements could be made. The sudden changes are interesting in that shifts were well over (estimated) 30-40 degrees and could have brought pesticide spray in the direction of my house had there been anything going on. The turbulence at low levels can be quite extreme and are likely to send spray clouds in various directions.


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