Quick Method for Open-Channel Discharge Measurements Using Air Bubbles

Yannopoulos, Panayotis C.; Demetracopoulos, Alexander C.; Hadjitheodorou, Ch.

doi:10.1061/(asce)0733-9429(2008)134:6(843)

Cited by 5 publications

(4 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Under different settings, however, the method may show promise, and avenues exist for overcoming the challenges experienced in this experiment. For example, researchers are using digital instrumentation [13] and cameras with image processing algorithms [22] to enhance the utility of the rising air bubble method.…”

Section: Rising Air Bubble Methodsmentioning

confidence: 99%

“…These methods were tested in an experimental flume to determine their ability to measure velocity under varying flow and substrate conditions, as well as to evaluate the ability to standardize the equipment and make repeat measurements. The four stream velocity measurement methods selected include the surface float, velocity head rod [10] [11], rising body, and rising air bubble methods [12] [13].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Laboratory assessment of alternative stream velocity measurement methods

Hundt

Blasch

2019

PLoS ONE

View full text Add to dashboard Cite

Understanding streamflow in montane watersheds on regional scales is often incomplete due to a lack of data for small-order streams that link precipitation and snowmelt processes to main stem discharge. This data deficiency is attributed to the prohibitive cost of conventional streamflow measurement methods and the remote location of many small streams. Expedient and low-cost streamflow measurement methods used by resource professionals or citizen scientists can provide scientifically useful solutions to this data deficiency. To this end, four current velocity measurement methods were evaluated in a laboratory flume: the surface float, rising body, velocity head rod, and rising air bubble methods. The methods were tested under a range of stream velocities, cross-sectional depths, and streambed substrates. The resulting measurements provide estimates of precision and bias of each method, as well as method-specific insight and calibration formulas. The mean values of the coefficient of variation, a measure of precision, were 10% for the surface float, 10% for the velocity head rod, 14% for the rising body, and 9% for the air bubble method. The values of scaled mean error, a measure of bias, were -8% for the surface float, -4% for the velocity head rod, -1% for the rising body, and 4% for the air bubble. The velocity head rod and surface float methods were the easiest methods to use, providing greater precision at large (> = 0.6 m/s) and small (<0.6 m/s) velocities, respectively. However, the reliance on a velocity ratio for each of these methods can generate inaccuracy in their results. The rising body method is more challenging to execute and of lower precision than the former two methods but provides low bias measurements. The rising air bubble method has a complex instrument assembly that is considered impractical for potential field user groups.

show abstract

Section: Rising Air Bubble Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Laboratory assessment of alternative stream velocity measurement methods

Hundt

Blasch

2019

PLoS ONE

View full text Add to dashboard Cite

show abstract

“…Several authors (e.g. Sargent, 1982b;Toop et al, 1997;Yannopoulos et al, 2008) have shown that applying this assumption depends on the air pressure, the size of the nozzle from which the air bubble is released, and water properties like turbulence, temperature and contamination. More detailed research on the motion of gas bubbles in a liquid has been performed by, amongst others, Aybers and Tapucu (1969a,b) and Lehrer (1980).…”

Section: Rising Velocitymentioning

confidence: 99%

“…Sargent's work meant a large advance with respect to applicability and accuracy of the method. However, since Sargent's publications, the method has only been applied by a few authors (Toop et al, 1997;Yannopoulos et al, 2008), suggesting that previous technologies made the method less easy and more expensive to apply compared to other gauging methods. A discussion of Sargent's work confirms this (Sargent and Davis, 1981).…”

Section: Introductionmentioning

confidence: 99%

Technical Note: How image processing facilitates the Rising Bubble Technique for discharge measurement

Hilgersom¹,

Luxemburg²

2011

Preprint

View full text Add to dashboard Cite

In this article, we rehabilitate the integrating rising bubble technique as an effective means of obtaining discharge measurements. Since Sargent (1981, 1982a), the technique has not been applied widely, mainly as a result of practical difficulties. We hypothesize that modern image processing techniques can greatly improve the rising bubble technique. We applied the technique in both a laboratory setup and a field study, after calibrating the bubble rising velocity for our nozzles in the specific case. During our measurements, we captured digital photographs of the bubble envelope at the water surface, each picture being a single measurement of the discharge. The photographs were corrected for lens distortion and reprojected so that accurate distances on water surface level could be obtained. This easy digital procedure resulted in accurate discharge measurements, even when turbulence was involved and the averages of multiple image analyses yielded good results. The study shows that the rising bubble technique can be a preferable discharge gauging technique in some situations. Recent developments in image processing facilitate the method substantially

show abstract