Choked Flows through Short Contractions

Wu, Baosheng; Molinas, Albert

doi:10.1061/(asce)0733-9429(2001)127:8(657)

Cited by 15 publications

(2 citation statements)

References 9 publications

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“…It was recommended to branch the Helium metering system to at least 3 units so that the effective flow rate through each regulator was reduced. the mass flow rate through it was determined based on empirical relations (Wu & Molinas 2001). To this end, the mass flow rate was measured by placing helium bottle(s) on a sensitive digital scale (± 0.01 lbs) and recording the change in weight of the bottle with time.…”

Section: Mass Flow Rate Calibrationmentioning

confidence: 99%

Statistically steady measurements of Rayleigh-Taylor mixing in a gas channel

Banerjee

Andrews

2006

Physics of Fluids

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A novel gas channel experiment was constructed to study the development of high Atwood number Rayleigh-Taylor mixing. Two gas streams, one containing air and the other containing helium-air mixture, flow parallel to each other separated by a thin splitter plate. The streams meet at the end of a splitter plate leading to the formation of an unstable interface and of buoyancy driven mixing. This buoyancy driven mixing experiment allows for long data collection times, short transients and was statistically steady. The facility was designed to be capable of large Atwood number studies of AB t B ~ 0.75. We describe work to measure the self similar evolution of mixing at density differences corresponding to 0.035 < AB t B < 0.25. Diagnostics include a constant temperature hot-wire anemometer, and high resolution digital image analysis. The hot-wire probe gives velocity, density and velocity-density statistics of the mixing layer. Two different multi-position single-wire techniques were used to measure the velocity fluctuations in three mutually perpendicular directions. Analysis of the measured data was used to explain the mixing as it develops to a self-similar regime in this flow. These measurements are to our iv knowledge, the first use of hot-wire anemometry in the Rayleigh-Taylor community.Since the measurement involved extensive calibration of the probes in a binary gas mixture of air and helium, a new convective heat transfer correlation was formulated to account for variable-density low Reynolds number flows past a heated cylinder. In addition to the hot-wire measurements, a digital image analysis procedure was used to characterize various properties of the flow and also to validate the hot-wire measurements. A test of statistical convergence was performed and the study revealed that the statistical convergence was a direct consequence of the number of different large three-dimensional structures that were averaged over the duration of the run.

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Section: Mass Flow Rate Calibrationmentioning

confidence: 99%

Statistically steady measurements of Rayleigh-Taylor mixing in a gas channel

Banerjee

Andrews

2006

Physics of Fluids

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“…Many researchers investigated the contractions in open channels among of them [10], [11], [18], [19] and [21]. Fahmy and Nassar [2] investigated flow and scour characteristics under effect of contraction upstream abutments.…”

Section: Introductionmentioning

confidence: 99%

The Afflux Calculation Under Effect of Different Number of Vents Experimentally and Using HEC-RAS

نصار¹

2022

JES. Journal of Engineering Sciences

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The effect of vents' number in bridges for the same contraction ratio was not taken into consideration in many calculation formulas of afflux. The present paper investigates the influence of vents' number on the calculation of the afflux through bridge for the same contraction ratio. The paper experimentally and numerically modeled the water surface profile through the bridge vents to calculate the afflux. The experimental measurements include two stages, the first stage includes the use of a single pier model with a length of 14.7 cm and a width of 2.3 cm. The second stage includes the presence of two piers of 14.7 cm length and 1.15 cm width for each one. The numerical modeling was done using one-dimensional River Analysis System (HEC-RAS). The results showed that the afflux ratio increased as Froude number increased. The increasing of vents' number for the same contraction ratio increases the afflux. The case of contraction ratio = 0.623 gives the higher values of the afflux ratio comparing other contraction ratios. The numerical modeling is promising compared the experimental measurements.

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