Sanford Ballard, Principle Investigator, SNL
Video 1.3 (:30)

Task Description

This in situ flow sensor technology (Video 1.3) uses a thin cylinder heater buried vertically in the ground at the point where the groundwater flow is to be mea-

sured (Figure 1.3). The tempera-
ture distribution over the surface of the cylinder will vary as a func-
tion of the magnitude and direc-
tion of the groundwater flow past the cylinder. In the absence of any flow past the device, the tempera-
ture on the surface of the probe will be independent of azimuth and symmetric about the vertical midpoint of the probe. Ground-
water flow past the device per-
turbs the surface temperature distribution of the sensor, with the pattern and magnitude of the tem-
perature variations reflecting the direction and magnitude of the groundwater flow velocity.

In essence, relatively warm tem-
peratures will be observed on the downstream side and relatively cool temperatures on the up-