The Study of Mengkuang Dam`s Chute Spillway by Physical Modeling

2015 ◽  
Vol 802 ◽  
pp. 63-67
Author(s):  
Che Mohamad Amirus Shafiq Che Ismail ◽  
Mohd Remy Rozainy Mohd Arif Zainol
Keyword(s):  
Water Level ◽  
Physical Model ◽  
Physical Modeling ◽  
Flow Direction ◽  
Vertical Direction ◽  
Equal Distance ◽  
Geometrical Scale ◽  
Velocity Pressure ◽  
Downstream Area

This paper presents a case study of water flow over the chute spillway type for the Mengkuang Dam expansion project. It governs the surplus water from the dam to the downstream area. However, flows were driven by gravity along the curvature and vertical direction which cause unpredictable flow direction along the chute. Its cause’s thickening of turbulence, changing the velocity, pressure and depth of the water along the spillway. This study was simulated using a physical model with geometrical scale of 1:20. After some test conducted on the spillway, eleven locations on the spillway were selected for the test based on observation for the study. For each location, there were five points in a line with equal distance. Manometers were installed on six locations of the spillway. The water level, velocity and pressure were measured at every point for 100, 1000, 10000 years and PMF design discharge of the spillway. Several critical occurrences on the spillway such as turbulent and cross-wave were presented in this paper.

Underwater high-precision ultrasonic water level measurement method for hydraulic physical model

2020 ◽  
Vol 28 (9) ◽  
pp. 2027-2034
Author(s):  
Yue-jie SHU ◽  
◽  
Jun WU ◽  
Yuan-hang ZHOU ◽  
Yu-feng MA ◽  
...  
Keyword(s):  
Water Level ◽  
Physical Model ◽  
High Precision ◽  
Measurement Method ◽  
Level Measurement

scholarly journals Significance of Slippage and Electric Field in Mucociliary Transport of Biomagnetic Fluid

Lubricants ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 48
Author(s):  
Sufian Munawar
Keyword(s):  
Shear Stress ◽  
Flow Direction ◽  
Pressure Rise ◽  
Physical Parameters ◽  
Slippage Effect ◽  
Channel Surface ◽  
Electro Osmosis ◽  
Biomagnetic Fluid ◽  
Velocity Pressure ◽  
Metachronal Waves

Shear stress at the cilia wall is considered as an imperative factor that affects the efficiency of cilia beatings as it describes the momentum transfer between the fluid and the cilia. We consider a visco-inelastic Prandtl fluid in a ciliated channel under electro-osmotic pumping and the slippage effect at cilia surface. Cilia beating is responsible for the stimulation of the flow in the channel. Evenly distributed cilia tend to move in a coordinated rhythm to mobilize propulsive metachronal waves along the channel surface by achieving elliptic trajectory movements in the flow direction. After using lubrication approximations, the governing equations are solved by the perturbation method. The pressure rise per metachronal wavelength is obtained by numerically integrating the expression. The effects of the physical parameters of interest on various flow quantities, such as velocity, pressure gradient, pressure rise, stream function, and shear stress at the ciliated wall, are discussed through graphs. The analysis reveals that the axial velocity is enhanced by escalating the Helmholtz–Smoluchowski velocity and the electro-osmosis effects near the elastic wall. The shear stress at the ciliated boundary elevates with an increase in the cilia length and the eccentricity of the cilia structure.

scholarly journals Comparative Analysis of Different Mobile LiDAR Mapping Systems for Ditch Line Characterization

2021 ◽  
Vol 13 (13) ◽  
pp. 2485
Author(s):  
Yi-Chun Lin ◽  
Raja Manish ◽  
Darcy Bullock ◽  
Ayman Habib
Keyword(s):  
Flow Direction ◽  
Sediment Accumulation ◽  
Digital Terrain Model ◽  
Vertical Direction ◽  
Point Clouds ◽  
Lidar Data ◽  
Cross Sectional ◽  
Premature Failure ◽  
3D Point Clouds ◽  
Mapping Systems

Maintenance of roadside ditches is important to avoid localized flooding and premature failure of pavements. Scheduling effective preventative maintenance requires a reasonably detailed mapping of the ditch profile to identify areas in need of excavation to remove long-term sediment accumulation. This study utilizes high-resolution, high-quality point clouds collected by mobile LiDAR mapping systems (MLMS) for mapping roadside ditches and performing hydrological analyses. The performance of alternative MLMS units, including an unmanned aerial vehicle, an unmanned ground vehicle, a portable backpack system along with its vehicle-mounted version, a medium-grade wheel-based system, and a high-grade wheel-based system, is evaluated. Point clouds from all the MLMS units are in agreement within the ±3 cm range for solid surfaces and ±7 cm range for vegetated areas along the vertical direction. The portable backpack system that could be carried by a surveyor or mounted on a vehicle is found to be the most cost-effective method for mapping roadside ditches, followed by the medium-grade wheel-based system. Furthermore, a framework for ditch line characterization is proposed and tested using datasets acquired by the medium-grade wheel-based and vehicle-mounted portable systems over a state highway. An existing ground-filtering approach—cloth simulation—is modified to handle variations in point density of mobile LiDAR data. Hydrological analyses, including flow direction and flow accumulation, are applied to extract the drainage network from the digital terrain model (DTM). Cross-sectional/longitudinal profiles of the ditch are automatically extracted from the LiDAR data and visualized in 3D point clouds and 2D images. The slope derived from the LiDAR data turned out to be very close to the highway cross slope design standards of 2% on driving lanes, 4% on shoulders, and a 6-by-1 slope for ditch lines.

Influence of the Blade-Spoke Connection Point on the Aerodynamic Performance of Darrieus Wind Turbines

2016 ◽  
Author(s):  
Alessandro Bianchini ◽  
Francesco Balduzzi ◽  
Giovanni Ferrara ◽  
Lorenzo Ferrari
Keyword(s):  
Wind Turbines ◽  
Design Parameter ◽  
Flow Direction ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Common Solution ◽  
Curvature Effects ◽  
Flow Curvature ◽  
Low Incidence

The assessment of robust CFD techniques is casting new light on the aerodynamics of airfoils rotating around an axis orthogonal to flow direction, with particular reference to flow curvature effects and stall mechanisms. In particular, Darrieus wind turbines’ designers are taking profit from these new discovers to improve the aerodynamic design of the rotors, in view of an increase of the overall efficiency and a reduction of the structural stresses on the blades. A controversial design parameter for Darrieus turbines, especially in case of small-size rotors, is represented by the location of the blade-spoke connection along the chord. The most common solution is indeed to place the connection at approximately airfoil’s quarter chord, i.e. where the pressure center is commonly located for low incidence angles. In some cases, however, the blade is connected at middle chord due to symmetry or aesthetic reasons. In some small turbines, innovative designs have even disregarded this parameter. Even if one can argue that the blade connection point is about to have some aerodynamic effects on the turbine’s performance, the real impact of this important design parameter is often not fully understood. The present study makes use of extensive CFD simulations on a literature case study, using a NACA 0021 airfoil, to assess the influence of the blade-spoke connection point. In particular, the differences in terms of power coefficient curve of the turbine, optimal tip-speed ratio, torque profiles and stresses on the connection are analyzed and discussed. Detailed flow analyses are also shown for azimuthal positions of particular interest. Results on the selected case study showed that the middle-chord blade-spoke connection point seems to guarantee a higher performance of the rotor, even if additional solicitation is applied to the connection itself. It is further shown that the same performance can indeed be obtained with the airfoil attached at quarter chord and properly pitched. By doing so, the stresses are contained and the performance is maximized.

Innovative real-time sensing of flow dynamics in groundwater and sediments to map contaminant spreading

2021 ◽  
Author(s):  
Goedele Verreydt ◽  
Niels Van Putte ◽  
Timothy De Kleyn ◽  
Joris Cool ◽  
Bino Maiheu
Keyword(s):  
Surface Water ◽  
Groundwater Flow ◽  
Real Time ◽  
Flow Direction ◽  
Flow Dynamics ◽  
Sensor Data ◽  
Time Data ◽  
Mass Fluxes ◽  
First Case

<p>Groundwater dynamics play a crucial role in the spreading of a soil and groundwater contamination. However, there is still a big gap in the understanding of the groundwater flow dynamics. Heterogeneities and dynamics are often underestimated and therefore not taken into account. They are of crucial input for successful management and remediation measures. The bulk of the mass of mass often is transported through only a small layer or section within the aquifer and is in cases of seepage into surface water very dependent to rainfall and occurring tidal effects.</p><p> </p><p>This study contains the use of novel real-time iFLUX sensors to map the groundwater flow dynamics over time. The sensors provide real-time data on groundwater flow rate and flow direction. The sensor probes consist of multiple bidirectional flow sensors that are superimposed. The probes can be installed directly in the subsoil, riverbed or monitoring well. The measurement setup is unique as it can perform measurements every second, ideal to map rapid changing flow conditions. The measurement range is between 0,5 and 500 cm per day.</p><p> </p><p>We will present the measurement principles and technical aspects of the sensor, together with two case studies.</p><p> </p><p>The first case study comprises the installation of iFLUX sensors in 4 different monitoring wells in a chlorinated solvent plume to map on the one hand the flow patterns in the plume, and on the other hand the flow dynamics that are influenced by the nearby popular trees. The foreseen remediation concept here is phytoremediation. The sensors were installed for a period of in total 4 weeks. Measurement frequency was 5 minutes. The flow profiles and time series will be presented together with the determined mass fluxes.</p><p> </p><p>A second case study was performed on behalf of the remediation of a canal riverbed. Due to industrial production of tar and carbon black in the past, the soil and groundwater next to the small canal ‘De Lieve’ in Ghent, Belgium, got contaminated with aliphatic and (poly)aromatic hydrocarbons. The groundwater contaminants migrate to the canal, impact the surface water quality and cause an ecological risk. The seepage flow and mass fluxes of contaminants into the surface water were measured with the novel iFLUX streambed sensors, installed directly in the river sediment. A site conceptual model was drawn and dimensioned based on the sensor data. The remediation concept to tackle the inflowing pollution: a hydraulic conductive reactive mat on the riverbed that makes use of the natural draining function of the waterbody, the adsorption capacity of a natural or secondary adsorbent and a future habitat for micro-organisms that biodegrade contaminants. The reactive mats were successfully installed and based on the mass flux calculations a lifespan of at least 10 years is expected for the adsorption material.  </p>

Estimating the ratio of pond size to irrigated soybean land in Mississippi: a case study

2016 ◽  
Vol 16 (6) ◽  
pp. 1639-1647 ◽  
Author(s):  
Ying Ouyang ◽  
Gary Feng ◽  
John J. Read ◽  
Theodor D. Leininger ◽  
Johnie N. Jenkins
Keyword(s):  
Water Level ◽  
Groundwater Resources ◽  
Pond Water ◽  
Crop Land ◽  
Experimental Learning ◽  
Storage Pond ◽  
Pond Size ◽  
Stella Model ◽  
On Farm

Although more on-farm storage ponds have been constructed in recent years to mitigate groundwater resources depletion in Mississippi, little effort has been devoted to estimating the ratio of on-farm water storage pond size to irrigated crop land based on pond metrics and its hydrogeological conditions. In this study, two simulation scenarios were chosen to determine such a ratio as well as to investigate pond hydrological processes using a Structural Thinking, Experimental Learning Laboratory with Animation (STELLA) model, one scenario with and the other without using pond water for irrigation for a typical pond that represented the average conditions in East Mississippi. Simulation results showed that pond water level changed moderately for conditions without using its water for irrigation, whereas pond water level changed dramatically for conditions with using its water for irrigation. A reasonable ratio of pond size to irrigated soybeans land was 1:18 if the irrigation rate was 2.54 cm/d (or 1 inch/d) and the low limit of the pond water level was drawn to near zero (0.08 m). For the ratio of 1:18, our simulations further revealed that a 1-ha soybeans land could save about 542 m3 groundwater each year. This study suggests that the STELLA model is a useful tool for estimating the ratio of pond size to irrigated crop land.

Behavior and Distribution of Nonylphenol Ethoxylates and their Metabolites in Sediments of Nansi Lake, China

2011 ◽  
Vol 356-360 ◽  
pp. 1733-1738
Author(s):  
Fang He ◽  
Aya Obara ◽  
Shi Long Wang ◽  
Li Guo Wang
Keyword(s):  
Water Flow ◽  
Flow Direction ◽  
Sediment Cores ◽  
Sewage Treatment ◽  
Vertical Direction ◽  
Total Content ◽  
Horizontal Distribution ◽  
Nansi Lake ◽  
Increasing Trend ◽  
Vertical And Horizontal Distribution

The vertical and horizontal distribution of NPEOn and their metabolites of NP and NPEnC in the Upper Nansi Lake, North China were investigated using LC-MS and LC-MS/MS methods, sampling at three sites (St.1, St.2 and St.3) along the water flow direction. The total content of NPEOn (n=1–15) bound onto the sediment of this lake changed in the range of 60.7–631.5 μg/kg-dry with the horizontal flow direction and the vertical direction of the sediment cores with sediment thickness up to 35 cm. Compared to the presence levels of all detected NPEOn species, the content of NP was much higher, falling in 26.5–1,998.4 μg/kg-dry. A general increasing trend of the NP content along the water flow direction of this lake was revealed. NPEnC showed a roughly increasing trend from the upstream to the downstream, with the total concentrations being obviously lower than NPEOn and NP and falling in 2.13–23.1 μg/kg-dry. The short chain NPEOn dominant in NPEO mixtures in these sedimentary cores indicated that this lake received some effluents from STPs, and the sewage treatment ratio is relatively low in this area. Furthermore, the computed magnitudes of NPEO 1-2/NPEO1-15, NP/NPEO 1-15 and NPEC 1-10/NPEO 1-15 suggested that the non-oxidative hydrolytic transformation seemed to be a major process occurring within the sediment phase of Nansi Lake, while the oxidative hydrolytic transformation pathway was probably less involved.

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