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Abandoned mine gobs contain a considerable amount of methane. Determining the methane flow space scientifically will directly affect the methane extraction of abandoned mine gobs. In this paper, a method is proposed to determine the gob methane flow space, based on the geological conditions of the Yongan abandoned mine in China. Physical simulation experiments were firstly conducted to simulate the abandoned gob formations. Subsequently, gas injection experiments were adopted to study the methane concentration distribution in the simulated gobs. The methane flow space was then determined based on the obtained methane concentration distribution. The results demonstrate that the methane flow space of abandoned mine gobs can be divided into four zones from the bottom to the top: methane high-concentration zone (MHZ), methane transition zone (MTZ), methane enrichment zone (MEZ) and methane no-stream zone (MNZ). The boundaries of these zones consistently exhibit a ‘V’ shape. The methane concentration in the MHZ is evidently higher than those in the MTZ and MEZ. The MTZ restrains the methane flow and causes a sharp decrease of the methane concentration in it. The methane in the MEZ is enriched as one shifts upwards and its concentration increases exponentially. Methane is absent in the MNZ. Based on these results, two surface vertical boreholes of the Yongan abandoned mine were selected to set their bottoms into the MEZ and MHZ, respectively. The field testing results demonstrate that the methane drainage flow rate at the bottom of the borehole located in the MHZ can increase by 1.5 times than that in the MEZ.

Objective To evaluate an alternative catheter labelling approach for 3-way catheters based on the drainage channel and irrigation channel cross-sectional area (CSA), which impacts catheter flow rate characteristics. Materials and Methods Three-way 22Fr catheters from Bard (Bard Limited), Rusch Simplastic (Teleflex Medical), Dover (COVIDIEN), and Rusch Golden were included in the study. Irrigation channel, drainage channel, and overall CSAs were digitally measured with an image-processing program. Irrigation channel and drainage channel flow rates were measured and correlated with their corresponding catheter CSA values. Results Catheter CSA and French value did not predict flow-rate characteristics, but irrigation channel CSA and drainage channel CSA were predictive. The 22Fr Rusch Simplastic catheter had the largest irrigation channel CSA (2.87 mm 2 ) and drainage channel CSA (12.6 mm 2 ), and had the greatest irrigation (5.27 ± 0.02 ml/s) and drainage flow rates (14.42 ± 0.22 ml/s). Twenty-two French gauge Rusch Golden catheters had the smallest irrigation channel CSA (1.34 mm 2 ) and drainage channel CSA (7.82 mm 2 ) and the lowest irrigation (1.83 ± 0.03 ml/s) and drainage flow rates (1.83 ± 0.03 ml/s). Conclusion An alternative catheter labelling system to include overall CSA, irrigation channel CSA, and drainage channel CSA values would provide more accurate and transparent data relevant to anticipated drainage and irrigation flow rates. The proposed labelling method will assist urologists in selecting 3-way catheters for bladder irrigation.

Gullies are devices that connect the surface system to the sewer allowing the drainage of water during a rainfall event. During severe flooding, the sewer might become pressurized and water may gush out of the sewer onto the surface, in what is termed reverse flow. Experimental and numerical studies of gullies are rare because of the high computational time and the experimental facilities costs. In this paper we aim to characterize the average velocity inside a gully at the center profile and discuss the qualitative air-entrainment structure for both drainage and reverse flow conditions. The experimental facility termed the Multiple-Linking-Element experiment (MLE) is located at the University of Coimbra. OpenFOAM™ v.1.7.1 is used with the Large Eddy Simulation (LES) Smagorinsky model to simulate turbulence. Numerical and experimental results show reverse flow with a strong jet at the center and an anticlockwise vortex on the left side of the gully box, and drainage flow with a large clockwise vortex located above and slightly to the left of the bottom outlet. Reverse flow shows few traces of air-entrainment, unlike drainage flow that exhibits large quantities of air-entrainment caused by a hydraulic jump formed on the surface flow.

Ligeia Mare, the second largest sea on Titan, resides in an endorheic basin dominated by seas in the northeastern polar region. Ligeia's shoreline morphology resembles terrestrial man-made reservoirs where water is dammed and valleys are flooded. Here we describe the mare and surrounding geologically diverse terrain including rugged highlands and lowlands, incised valleys, and smooth plains. Observations include active processes evidenced by drainage flow directions, areal extent of rivers and river valleys, sediment volume estimates, and varied drainage patterns. Headward erosion has carved valley and ridge systems in the flanks of the highlands, while the more distal highland plateau is mostly uncut by rivers or extensive erosion and contains smaller lakes, lakebeds, and mottled terrain.

Geological storage of CO2 in deep saline aquifers is achieved by injecting CO2 into aquifers and displacing the brine. Although most of the groundwater is displaced, some residual groundwater remains in the rock pores. We conducted experiments to investigate the formation process of residual water. Rock samples were saturated with brines of different concentrations. CO2 was injected into the samples at aquifer temperature and pressure, and the drained water was measured. The results show that the groundwater drainage was slower and the irreducible water saturation was higher with higher brine concentration. The process of drainage can be classified into three stages according to the drainage flow rates: piston drainage, portable drainage, and dissolved drainage.

This paper describes the simulation of the most important characteristics of the flow and temperature fields observed during the tracer release of the 1990 TRANSALP campaign. The goal of the campaign was to follow the tracer from Leventina Valley to the other side of the Alpine range to investigate whether a re-circulation process could occur due to the valley and mountain breezes. Model output is compared with observations of wind and temperature over an entire day (29 September 1990). Meteorological measurements were obtained at a number of ground stations. Vertical wind and temperature profiles were also available. Model initialization was performed using airborne meteorological measurements and profiles from the synoptic station of Payerne. RAMS results correctly describe the generation of the drainage flow during the night and the successive formation of the valley breeze due to the difference in temperature gradients in the various valleys of the domain. Simulated windfields are in general more accurate during the daytime than during the night hours, since vertical variability in stable conditions is more difficult to reproduce.

Procedures for drainage basin delineation and modeling of drainage flow accumulation are provided for single instruction stream, multiple data stream (SIMD) computers. Performance statistics were gathered from a series of windows on a DEM and analyzed for an implementation of the procedures, written in C ∗ and executed on a Thinking Machines CM-5 in SIMD mode. Results of the analysis show that the SIMD implementation completes execution in less than one-half the time of a comparable sequential implementation when both are run over the largest window. The results also show that execution times for the SIMD implementation initially increase linearly with the ratio of virtual processors to physical processors.

Perforated draintubes have, in many places, supplanted the use of draintiles in drainage systems of agricultural lands, airports, structural foundations, etc. This indicates that there is a need to obtain analytical solutions of the drainage flow rate for perforated draintubes. By using a series solution of Laplace's equation and techniques of solution of dual trigonometric series, a formula for the flow rate into a draintube buried in a water-saturated soil medium is developed. The flow rate into a draintube depends on numerous characteristics such as the hole size, the number and spacing of holes, the drain size and depth. Graphs showing the variation in delivery ratio with respect to geometric characteristics of draintubes are presented.

Nocturnal cold air drainage was examined in corn and oak canopies, and over a bare field on a hillside in Storrs, Connecticut. Smoke tracers, and vertical profiles of wind and temperature showed drainage flow development and persistence to be markedly affected by surface cover. In corn, the drainage flow maximums were in the order of 1 m s −1 above the canopy and 0.4 m s −1 inside the canopy. In the leafed hardwood forest, drainage flow only developed above the canopy. Only ground drainage flows developed in the forest during the leafless phase. Cold air drainage flows within the corn and leafless oak canopies were often maintained during periods of high local windspeeds (> 5 m s −1 ) when drainage flow above the canopies and over bare ground was no longer apparent. Measured flow rates were compared to predicted rates from models developed by Fleagle, and Petkovsek and Hocevar. We found the form assumed for the frictional force in these models inadequate for use with katabatic air flows in tall roughness elements. In some cases the Cionco canopy flow model, modified for stability, simulated the within canopy flows.

Cooling tower plume rise measurements are required for evaluation and validation of cooling tower plume rise models. In August 1981, five cooling tower plume defining experiments were conducted at the Geysers Geothermal Area in California during both valley nocturnal drainage flow conditions, and diurnal limited vertical mixing conditions on a mountain ridge. Sequential 300-s time integrated photographs of the plumes were made for several hours during each experiment. Time lapse movies were also made during the daytime experiments. Meteorological conditions were measured during all experimental periods by tethersonde and rawinsonde. The time integrated photographs have been analyzed to provide values of plume rise heights vs time for each of the experiments. Predictions by one version of the Argonne National Laboratory plume rise model are within a factor of 2 of the plume rise calculated from the photographs.

A numerical study of steam condensation over horizontal fluted tubes is presented. Condensate is driven by surface tension to the groove valley where it is drained by gravity. From the bottom to the top the groove domain is divided into a valley section, crest section with large variations of condensate layer curvature, and tip section with gradual change of condensate layer curvature. In the valley section the effect of indentation angle α, the minimum condensate height α o and the circumferential angle θ on the drainage flow rate ·m are studied. In the crest section ( heat transfer domain ) the effect of α, α o and θ on the heat transfer coefficient h is investigated. Results showed that, a decrease in α increases both h, and ·m per groove. The groove flooding conditions could be obtained by comparing ·m in the valley and crest sections with more flooding for small values of α. The smaller the α angle, the larger the ·m provided that no excessive flooding occurs.

The fate of SO_2 emitted in the San Joaquin Valley of California under stagnant foggy conditions was determined by the release of an inert tracer and the concurrent monitoring of SO_2 and SO_4^(2−) concentrations. At night, SO_2 was found to be trapped in a dense fog layer below a strong and persistent inversion based a few hundred meters above the valley floor. This lack of ventilation led to the accumulation of SO_2 and SO_4^(2−) over a major SO_2 source region in the valley. The rate of oxidation of SO_2 to SO_4^(2−) in fog was estimated at 3 ± 2%h^(−1). Production of acidity from the oxidation of SO_2 fully titrated the NH_3(g) present before the fog, and led to a progressive drop of the fogwater pH over the course of the night. In the afternoon, the valley was found to be efficiently ventilated by a buoyant upslope flow through the inversion. The tracer data indicated that about 40 % of the air transported upslope in the afternoon was returned to the valley in the night-time drainage flow. The fates of SO_2 and SO_4^(2−) in the valley during extended high-inversion episodes appear to depend considerably on the presence of fog or stratus, and on the extent of daytime insolation.