Water Profile over an Ogee-Shaped Crest and the Reynolds Fractional Equations

Weir crest must have the correct shape in the concave side of an ogee-shaped crest to diminish erosion. This shape can be obtained using an approximation of the fractional Reynolds equations when the water interacts with the surface. A model is introduced for the Reynolds stresses complemented with a closure relation of fractional origin. A power type solution is obtained for the main velocity and stress. Velocity profile is found based on the assumption of a steady flow and the energy conservation equation. A Froude number and the cubic equation of the weir are built. The dimensionless upstream velocity head is also determined which allow graphically showing the exponent and coefficient of the water-profile over an ogee-shaped crest. It is possible to estimate the occupied-space index trough an exponents＇ ratio of profile over the velocity head.

Impact of backwater on water surface profile in curved channels

Owing to extensive construction of dams, the impact of backwater on flow may lead to navigation or flood control issues in curved channels. To date, the impact of backwater on the water surface profile in curved channels remains unknown and requires investigation. In this study, experiments were conducted in a glass-walled recirculating flume with a length of 19.4 m, a width of 0.6 m, and a depth of 0.8 m, and the impact of backwater on the water surface profile in a 90° channel bend was investigated. The experimental results showed that the backwater degree had a significant impact on the transverse and longitudinal flow depth distributions in the bend. The transverse slope of the flow (Jr) increased linearly with an increase in the Froude number of the approach flow upstream of the bend. Jr increased with the longitudinal location parameter ξ when −0.2 < ξ < 0.5, and decreased with ξ when 0.5 < ξ < 1.2. Furthermore, the results showed that Jr asymptotically decreased to zero with an increase in the degree of backwater. An equation was formulated to estimate the transverse slope of the flow in a 90° bend in backwater zones.

The Effect of the Sinking of Isotope Grains in Water Injection Profile Logging

In the process of oil field exploitation, radioactive isotope tracer water injection profile logging is a main method to determine the water-intake capacity of the target intervals. For those general water injection wells, whose perforated intervals are beyond the tubing shoe, the sinking speed of isotope grains is related to the density and salinity of the injection water and the tubing dimension. We studied the motion of the isotope grains in the water injection wells by both theoretical calculation and field experiment. The result shows that if the water injection quantity is over 20 m＆3/d, and the density of the isotope grains, whose diameter is 100-600 μm, is 1.06 g/cm^3, then the logging technique for this kind of water injection wells will be appropriate. Whether water injection profile logging is successful in the well, whose perforated intervals are beyond the tubing shoe, depends on the sinking speed of the tracer grains.

Observation and modeling on irregular purple soil water infiltration process

The infiltration process is a critical link between surface water and groundwater. In this research, a specific device to observe infiltration processes in homogeneous and heterogeneous soils with triangular and inverted triangular profiles was designed, and the Green-Ampt model was employed for the process simulation. The results indicate that(1) the wetting front in coarse texture soils transports faster than in fine texture soils;(2) for the homogeneous case, the wetting front in triangularshaped soils transports faster than the inverted triangular type, but the triangular-shaped soils show a lower infiltration rate;(3) in the initial step, the wetting front in triangular-shaped soils shows higher transport speed, but depicts lower speed with increase in the time;(4) both the wetting front and infiltration rate show a significant exponential relation with the time. From these findings, an empirical model was developed which agrees well with the observed data and provides a useful method for this field of soil research.

Uniformity of Precipitation and Radial Profile of the Super 10 Sprinkler at Different Operating Pressures

The study aimed to evaluate the effect of operating parameters of the sprinkler Super 10, manufactured by NaanDanJain, with green, yellow and blue nozzles on the hydraulic characterization, so that this information can contribute to a better dimensioning of systems and management of irrigated areas. For the determination of UC and UD the radial method was used and with the aid of computer application CATCH 3D the overlapping of water slides with ten spacings was calculated. The results demonstrate that the mechanism used for the fractionation of the water jet of sprinkler Super 10 is efficient because it presented good uniformity of water distribution and low amplitude of precipitation. For high uniformity of distribution of water in the larger wetting radii, it is recommended to work with Super 10 sprinkler using the green nozzle, with a pressure of 40 mH2O and spacing between sprinklers and lateral lines 12 × 12 m.

Validation of IASI-Retrieved Atmospheric Water Vapor Data over the Tibetan Plateau Region

The Infrared Atmospheric Sounding Interferometer (IASI) is a new-generation ultraspectral atmospheric sounding instrument mounted on the MetOp-A, the first operational polar-orbiting satellite developed by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). It is an ultrahigh spectral-resolution atmospheric detector which can detect atmospheric chemical composition, temperature, and humidity profiles with high accuracy and resolution. In the present study, through comparative analyses of the similarities and differences between the IASI and the radiosonde observation (RAOB) water vapor data, and between the IASI and the Aqua-AIRS water vapor retrievals, a detailed and systematic assessment of the credibility of the IASI water vapor retrievals over the plateau region was made. A comparison of the IASI retrievals with the AIRS retrievals and the RAOB measurements over the Tibetan Plateau revealed that the IASI retrieval data are reliable and can be used for conducting further studies.

Production characteristics and displacement mechanisms of infilling polymer-surfactant-preformed particle gel flooding in post-polymer flooding reservoirs:A review of practice in Ng3 block of Gudao Oilfield

The pilot test of infilling polymer-surfactant-preformed particle gel(PPG)flooding has been successfully implemented after polymer flooding in Ng3 block of Gudao Oilfield in China.However,the production characteristics and displacement mechanisms are still unclear,which restricts its further popularization and application.Aiming at this problem,this paper firstly analyzes the production performance of the pilot test and proposed four response types according to the change of water cut curves,including W-type,U-type,V-type response,and no response.Furthermore,the underlying reasons of these four types are analyzed from the aspects of seepage resistance and sweep efficiency.The overall sweep efficiency of gradual-rising W-type,gradual-decreasing W-type,and early V-type response increases from 0.81 to 0.93,0.55 to 0.89,and 0.94 to 1,respectively.And the sum of seepage resistance along the connection line between production well and injection well for U-type and delayed V-type response increases from 0.0994 to 0.2425,and 0.0677 to 0.1654,respectively.Then,the remaining oil distribution after polymer flooding is summarized into four types on the basis of production and geological characteristics,namely disconnected remaining oil,streamline unswept remaining oil,rhythm remaining oil,and interlayer-controlled remaining oil.Furthermore,the main displacement mechanisms for each type are clarified based on the dimensionless seepage resistance and water absorption profile.Generally,improving connectivity by well pattern infilling is the most important for producing disconnected remaining oil.The synergistic effect of well pattern infilling and polymer-surfactant-PPG flooding increases the dimensionless seepage resistance of water channeling regions and forces the subsequent injected water to turn to regions with streamline unswept remaining oil.The improvement of the water absorption profile by polymer-surfactant-PPG flooding and separated layer water injection contributes to displacing rhythm remaining oil and interlayer-controlled remaining oil.Finally,the paper analyzes the relationships between the remaining oil distribution after polymer flooding and production characteristics of infilling polymer-surfactant-PPG flooding.The study helps to deepen the understanding of infilling polymer-surfactant-PPG flooding and has reference significance for more commercial implementations in the future.

Research progress and application prospect of functional adhesive materials in the field of oil and gas drilling and production

By summarizing the composition,classification,and performance characterization of functional adhesive materials,the adhesion mechanisms of functional adhesive materials,such as adsorption/surface reaction,diffusion,mechanical interlocking,and electrostatic adsorption,are expounded.The research status of these materials in oil and gas drilling and production engineering field such as lost circulation prevention/control,wellbore stabilization,hydraulic fracturing,and profile control and water plugging,and their application challenges and prospects in oil and gas drilling and production are introduced comprehensively.According to the applications of functional adhesive materials in the field of oil and gas drilling and production at this stage,the key research directions of functional adhesive materials in the area of oil and gas drilling and production are proposed:(1)blending and modifying thermoplastic resins or designing curable thermoplastic resins to improve the bonding performance and pressure bearing capacity of adhesive lost circulation materials;(2)introducing low-cost adhesive groups and positive charge structures into polymers to reduce the cost of wellbore strengthening agents and improve their adhesion performance on the wellbore;(3)introducing thermally reversible covalent bond into thermosetting resin to prevent backflow of proppant and improve the compressive strength of adhesive proppant;(4)introducing thermally reversible covalent bonds into thermoplastic polymers to improve the temperature resistance,salt-resistance and water shutoff performance of adhesive water shutoff agents.

Hydrochemistry of Rara Lake: A Ramsar lake from the southern slope of the central Himalayas,Nepal

High-altitude Himalayan lakes act as natural storage for environmental evidence related to climate change and environmental factors.A great number of lakes are distributed in the southern slope area of the central Himalayas;however,research concerning the hydrochemical processes of these lakes is still insufficient.Herein,we present a comprehensive study on the water chemistry of the lake waters and the inlet stream waters from Rara Lake in western Nepal based upon samples collected in November 2018.The p H,dissolved oxygen,chlorophyll-aconcentration(chl-a),water temperature,electric conductivity(EC)and total dissolved solids(TDS)were measured in situ,and the concentrations of major ions(Ca^(2+),Mg^(2+),K^(+),Na^(+),Cl^(-),SO_(4)^(2-),and NO_(3)^(-))were analyzed in the laboratory.The results revealed that the water in Rara Lake is slightly alkaline,with p H values ranging from 7.6-7.98.The cations,in decreasing order of concentration in the lake water,are Ca^(2+)>Mg^(2+)>K^(+)>Na^(+)with average concentrations of20.64 mg·L^(-1),11.78 mg·L^(-1),1.48 mg·L^(-1) and 0.72 mg·L^(-1),respectively;the order and concentrations for the anions is HCO_(3)^(-)>SO_(4)^(2-)>Cl^(-)>NO_(3)^(-),with average concentrations of 122.15 mg·L-1,2.15 mg·L-1,0.46mg·L-1 and 0.55 mg·L-1,respectively.The dominant cation and anion in the lake water are Ca2+and HCO3-and they account for 48.14%and 71.8%of the totals,respectively.The range of lake water TDS is from 95mg·L^(-1) to 98 mg·L^(-1),with an average of 96.85 mg·L^(-1).The high ratio of(Ca^(2+)+Mg^(2+))to total cations and the low ratio of(Na^(+)+K^(+))to total cations indicate that Rara Lake receives ions from rock weathering,especially from carbonate rocks.Similarly,Gibbs boomerang diagrams and Piper diagrams also support the hydrochemistry of Rara Lake as being dominated by rock-weathering patterns.Likewise,other statistical analysis tools,such as Principal Component Analysis(PCA)and correlation strongly suggest the dominance of weathering of calcium and magnesium bicarbonate rocks as the major source of ions in Rara Lake.However,several traces of anthropogenic inputs into the lake were noticed,and the hypolimnion in the lake appears to be oxygen deficient,which may not be an issue at present but cannot be ignored in the future.

A Computer Method of Steady Non-Uniform Gradually Varied Flow in Open Channel & in River

Most of water flow in open channel or in river belongs to steady non-uniform flow. The surface profiles are caused by changes of channel section. It is very important to analyze its computation. According to the regularity of its surface change, the suitable sectional dimensions of open channel or flood control work can be designed. Commonly, computation of non-uniform flow adopts the traditional methods by hand or by graphic method. The speed and precision of computation are restricted. In this paper, a software to calculate water surface profile is introduced. The software is put forward by using C++ .By means of interpolate method and dialogue between user and computer, we can calculate the water surface profile much more quickly and exactly.

Quantitative method to determine the regional drinking water odorant regulation goals based on odor sensitivity distribution:Illustrated using 2-MIB

Taste and odor （T/O） in drinking water often cause consumer complaints and are thus regulated in many countries. However, people in different regions may exhibit different sensitivities toward WO. This study proposed a method to determine the regional drinking water odorant regulation goals （ORGs） based on the odor sensitivity distribution of the local population. The distribution of odor sensitivity to 2-methylisobomeol （2-MIB） by the local population in Beijing, China was revealed by using a normal distribution function/model to describe the odor complaint response to a 2-MIB episode in 2005, and a 2-MIB concentration of 12.9 ng/L and FPA （flavor profile analysis） intensity of 2.5 was found to be the critical point to cause odor complaints. Thus the Beijing ORG for 2-MIB was determined to be 12.9 ng/L. Based on the assumption that the local FPA panel can represent the local population in terms of sensitivity to odor, and that the critical FPA intensity causing odor complaints was 2.5, this study tried to determine the ORGs for seven other cities of China by performing FPA tests using an FPA panel from the corresponding city. ORG values between 12.9 and 31.6 ng/L were determined, showing that a unified ORG may not be suitable for drinking water odor regulations. This study presents a novel approach for setting drinking water odor regulations.

Water surface profile prediction in non-prismatic compound channel using support vector machine(SVM)

The process of estimating the level of water surface in two-stage waterways is a crucial aspect in the design of flood control and diversion structures.Human activities carried out along the course of rivers,such as agricultural and construction operation,have the potential to modify the geometry of floodplains,leading to the formation of compound channels with non-prismatic floodplains,thus possibly exhibiting convergent,divergent,or skewed characteristics.In the current investigation,the Support Vector Machine(SVM)technique is employed to approximate the water surface profile of compound channels featuring narrowing floodplains.Some models are constructed by utilizing significant experimental data obtained from both contemporary and previous investigations.Water surface profiles in these channels can be estimated through the utilization of non-dimensional geometric and flow parameters,including:converging angle,width ratio,relative depth,aspect ratio,relative distance,and bed slope.The results of this study indicate that the SVM-generated water surface profile exhibits a high degree of concordance with both the empirical data and the findings from previous research,as evidenced by its R^(2) value of 0.99,RMSE value of 0.0199,and MAPE value of 1.263.The findings of this study based on statistical analysis demonstrate that the SVM model developed is dependable and suitable for applications in this particular domain,exhibiting superior performance in forecasting water surface profiles.