scholarly journals An Experimental and Numerical Comparison of Flow Hydraulic Parameters in Circular Crested Weir Using Flow3D

2016 ◽  
Vol 2 (1) ◽  
pp. 23-37 ◽  
Author(s):  
Farhad Ghazizadeh ◽  
M. Azhdary Moghaddam
Keyword(s):  
Water Discharge ◽  
Geometry Optimization ◽  
The Body ◽  
Numerical Comparison ◽  
Relative Depth ◽  
Flow Depth ◽  
Upstream Slope ◽  
Downstream Slope ◽  
Cfd Method ◽  
Distribution Energy

Circular crested weirs consist of a circular crested of upstream and downstream walls. These weirs are widely used in hydraulic engineering as water discharge structures and can be used to control water level in channels and tanks. In the present study, using Flow3D software, hydraulic properties were investigated to find weir geometry optimization through CFD method. Also, this study attempted to investigate flow on some sections of circular crested weirs in 3 groups and 11 models. Upstream and downstream slope changes as well as the height of the weir were also studied. To validate the model, laboratory models were used. In the research, flow depth parameters on crest, pressure distribution, velocity distribution, energy loss on circular crested weirs, as well as the height and changes of upstream and downstream slope were evaluated. Flow depth on the body of circular crest in this state is about 0.71 (H1). Upstream slope changes on flow depth on the weir’s crest revealed that increasing upstream slope causes to the increase of flow relative depth (H1/R) on the crest about 62%. Downstream changes in H1/R values less than 0.7 have no significant effect on discharge coefficient; however, increasing H1/R values seems to cause more change in slope.

scholarly journals Resource partitioning and ecomorphological variation in two syntopic species of Lebiasinidae (Characiformes) in an Amazonian stream

2016 ◽  
Vol 46 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Nathália Carina dos Santos SILVA ◽  
Aluízio José Lopes da COSTA ◽  
José LOUVISE ◽  
Bruno Eleres SOARES ◽  
Vanessa Cristine e Souza REIS ◽  
...  
Keyword(s):  
Resource Partitioning ◽  
Trophic Ecology ◽  
Species Coexistence ◽  
Stomach Contents ◽  
Relative Length ◽  
Niche Overlap ◽  
The Body ◽  
Feeding Strategies ◽  
Relative Depth ◽  
Feeding Niche

ABSTRACTResource partitioning is important for species coexistence. Species with similar ecomorphology are potential competitors, especially when phylogenetically close, due to niche conservatism. The aim of this study was to investigate the resource partitioning among populations of two species of lebiasinids (Copella nigrofasciata and Pyrrhulina aff. brevis) that co-occur in a first-order Amazonian stream, analyzing the trophic ecology, feeding strategies and ecomorphological attributes related to the use of food and space by these species. Fish were captured in May and September 2010. The stomach contents of 60 individuals were analyzed and quantified volumetrically to characterize the feeding ecology of both species. Eleven morphological attributes were measured in 20 specimens and combined in nine ecomorphological indices. Both species had an omnivorous-invertivorous diet and consumed predominantly allochthonous items. Both showed a tendency to a generalist diet, but intrapopulational variation in resource use was also detected. Overall feeding niche overlap was high, but differed between seasons: low during the rainy season and high in the dry season. In the latter, the food niche overlap was asymmetric because C. nigrofasciata consumed several prey of P. aff. brevis, which reduced its food spectrum. The ecomorphological analysis suggests that C. nigrofasciatahas greater swimming capacity (greater relative length of caudal peduncle) than P. aff. brevis, which has greater maneuverability and tendency to inhabit lentic environments (greater relative depth of the body). Our results demonstrate that these species have similar trophic ecology and suggest a spatial segregation, given by morphological differences related to locomotion and occupation of habitat, favoring their coexistence.

scholarly journals ANALISIS KEAMANAN LERENG BENDUNGAN UTAMA PADA BENDUNGAN BENEL DI KABUPATEN JEMBRANA

1970 ◽  
Author(s):  
I G. N. Putu Dharmayasa ◽  
I W. Redana ◽  
Tjok Gde Suwarsa Putra
Keyword(s):  
Water Level ◽  
Safety Factor ◽  
The Body ◽  
Security Requirements ◽  
Seismic Load ◽  
Dam Safety ◽  
Seepage Discharge ◽  
Minimum Requirement ◽  
Downstream Slope ◽  
Normal Water

Development of dam very important for community surrounding the dam. To maintain that the benefits can be continued, it is necessary to review whether the safety of dams already meet the expected requirements. Dam safety to be reviewed when the dam was built and when the dam operating at this time. Security conditions associated with changes in water level on the upstream dam that affects the seepage on the body of dam and seepage under the dam. The water level also affects the slope of the dam when the dam has been operating.  Evaluation of the safety of the dam was conducted on Benel dam which located in Melaya District, Jembrana Regency, Bali Province. The results of the calculation of seepage (q) in the dam body with SEEP/W and flownet shows that, seepage discharge (q) which passes through under the dam and the body of dam is less than 1% (4.9206 m3/second) against the average flood discharge, so it has met the security requirements. Dam safety factor calculations without seismic load and with seismic load, for upstream slope and downstream slope when the dam was constructed,  when operating with flood water level,  when operating in the rainy season (normal water level),  when operating in the dry season (minimum water level) and with rapid draw down condition, with SLOPE/W and the Bishop method, the safety factor obtained more than minimum requirement by RSNI M-03-2002.

Numerical Simulation of Ship Maneuvering Motions in Viscous Flow

2009 ◽  
Vol 419-420 ◽  
pp. 677-680
Author(s):  
Dong Li Li ◽  
Liang Yang ◽  
Hong Yu Zhang ◽  
Tian Shu Peng
Keyword(s):  
Numerical Simulation ◽  
Viscous Flow ◽  
Simulation Method ◽  
Turing Test ◽  
The Body ◽  
Ship Maneuvering ◽  
Motion Simulator ◽  
Real Size ◽  
Cfd Method ◽  
Viscous Flow Field

In this paper, based on CFD method and dynamic mesh technology, the ship maneuvering performance is predicted in viscous flow. Numerical computation models are built to realize the simulation of the ship maneuvering motions such as static drift test, static rudder test, pure yaw test and pure sway test. Hydrodynamic forces and moments acting on a maneuvering ship are obtained in the body-fixed coordinate system. The computational results are compared with data of potential theory method. Then based on VC code, a simulator of ship maneuvering motions is built to simulate ship Zigzagging and Turing test. The results show that the present numerical simulation method and the ship maneuvering motion simulator are able to be used in numerical simulation of the real size ship maneuvering motions in viscous flow field.

Seismic deformation analysis of Tuttle Creek Dam

2012 ◽  
Vol 49 (3) ◽  
pp. 323-343 ◽  
Author(s):  
Timothy D. Stark ◽  
Michael H. Beaty ◽  
Peter M. Byrne ◽  
Gonzalo Castro ◽  
Francke C. Walberg ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Constitutive Models ◽  
Deformation Analysis ◽  
East Central ◽  
Fine Grained ◽  
Upstream Slope ◽  
Downstream Slope ◽  
Soil Constitutive Models ◽  
Seismic Deformation

To facilitate the design of seismic remediation for Tuttle Creek Dam in east central Kansas, a seismic finite difference analysis of the dam was performed using the software FLAC and the UBCSAND and UBCTOT soil constitutive models. The FLAC software has a key advantage because it can use calibrated site-specific constitutive models. Earlier deformation analyses using a hyperbolic constitutive model for the foundation fine-grained materials did not properly represent the modulus and strength reduction and predicted extremely large permanent deformations. Cyclic triaxial laboratory tests using high-quality samples and in situ vane shear tests were used to calibrate the FLAC constitutive model herein. The resulting FLAC analysis of the unremediated dam predicted an upstream slope toe deformation of about 0.6 m, a crest settlement of about 0.6 m, and a downstream slope toe deformation of about 1.5 m using the design ground motion. Based on the estimated permanent deformations and other factors, it was decided that the anticipated upstream slope and crest deformations were tolerable and only the downstream slope had to be remediated to protect the downstream seepage control system.

Testing the Hypothesis of Labelled Detectors

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 113-113 ◽  
Author(s):  
A I Cogan
Keyword(s):  
The Body ◽  
Relative Depth ◽  
Weak Version ◽  
Strong Version ◽  
Specific Mechanism ◽  
Detection And Identification ◽  
Uncrossed Disparity ◽  
Complex Shapes ◽  
Neural Substrate ◽  
Additional Processing

The hypothesis of labelled detectors (or ‘lines’) is the present-day version of the basic Müller - Helmholtz doctrine. Müller's dictum of specific energy of nerves stated: “the same internal cause excites (…) in each sense the sensation peculiar to it”. Helmholtz made ‘the cause’ external to the body and postulated that all knowledge about the world thus comes through the senses. The key word is specificity. The strong version of the hypothesis must treat detection - identification as a single task: a stimulus would be identified whenever it is detected. The weak version requires only that we identify a specific mechanism by which both detection and identification are achieved, even though the latter may require additional processing. In the general case, the strong version (with its ludicrous ‘grandmother cell’ as the neural substrate) finds little support. Detection and recognition of complex shapes (letters, faces, etc) aside, even discrimination between simple increments and decrements of luminance is difficult to attribute directly to a specific mechanism (in this case, the activity in either ON or OFF systems, respectively). This is demonstrated by experiment 1 reported here. However, perception of relative depth seems to conform to the strong version of the hypothesis, as experiment 2, also reported here, indicates. Thus, at least some specific neural mechanisms (in this case, probably the crossed and uncrossed disparity detectors) may be indeed linked directly to perception.

scholarly journals Aerodynamics of Cycling Skinsuits Focused on the Surface Shape of the Arms

2021 ◽  
Vol 11 (5) ◽  
pp. 2200
Author(s):  
Sungchan Hong ◽  
Takeshi Asai
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Experiment ◽  
The Body ◽  
Surface Shape ◽  
Air Resistance ◽  
Computational Fluid Dynamics Cfd ◽  
Race Conditions ◽  
Cfd Method ◽  
Fabric Surface ◽  
Full Body

In cycling, air resistance corresponds to 90% of the resistance on the bicycle and cyclist and 70% of this is applied to the body of the cyclist. Despite research on postures that could reduce air resistance, few studies have been conducted on full-body cycling suits. As the aerodynamics of the surface shape of clothing fabric are still unclear, the airflow around cyclists and air resistance were examined using a computational fluid dynamics (CFD) method and wind tunnel experiment. Specifically, in this study, we focused on how different surface shapes of cycling suit fabrics affect air resistance. CFD results indicate that air resistance during a race was high at the head, arms and legs of the cyclist. In the wind tunnel experiment, a cylinder model resembling the arms was used to compare the aerodynamic forces of various fabrics and the results showed that air resistance changed according to the fabric surface shape. Moreover, by changing the fabric shape of the arms of the cycling suits, reduction of air resistance by up to 8% is achievable. These results suggest that offering the most appropriate suit type to each cyclist, considering race conditions, can contribute to further improvement in their performance.

scholarly journals Estimation of car air resistance by CFD method

2014 ◽  
Vol 36 (3) ◽  
pp. 235-244 ◽  
Author(s):  
Phan Anh Tuan ◽  
Vu Duy Quang
Keyword(s):  
Fluid Dynamics ◽  
Surface Area ◽  
Rolling Resistance ◽  
The Body ◽  
Ansys Fluent ◽  
Car Body ◽  
Air Resistance ◽  
Implicit Solver ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

Total car resistance is including rolling resistance and air resistance. Rolling resistance comes from car tires when it rolls over the roads with car weight. Air resistance comes from the body when it moves in the air with car body surface area. The air resistance of a car depends upon its shape. The bigger the surface area of a car body, the more air molecules the car will hit and so the larger the air resistance. This paper will mention to estimation of car air resistance by computational fluid dynamics (CFD) method. A 3D car body has used for simulation in ANSYS FLUENT CFD software. The k-\(\varepsilon\) turbulence model and segregated implicit solver was used to perform computation in this study.

scholarly journals SLOPE STABILITY ASSESSMENT OF THE UPSTREAM SLOPE OF THE DRY MOUNTAIN FLOOD CONTROL RESERVOIR DURING THE FLOOD

2021 ◽  
pp. 4-12
Author(s):  
Svitlana Velychko ◽  
Olena Dupliak ◽  
Tetiana Kurbanova
Keyword(s):  
Slope Stability ◽  
Water Level ◽  
Flood Control ◽  
Limit Equilibrium ◽  
High Water ◽  
Limit Equilibrium Method ◽  
Water Levels ◽  
The Body ◽  
Stability Assessment ◽  
Upstream Slope

The flood control is one of the priority goal for successful economic activity on the areas that are periodically suffer from floods. Such areas are the mountainous regions of the Ukrainian Carpathian Mountains. Floods on the mountain rivers are repeated several times each year, and are characterized by the sudden water level rise with almost the same rapid decrease of the water level. Active flood protection measures include dry mountain flood control reservoirs, the principle of which is to transform part of the flood runoff and to accumulate water for the short time in the the artificial reservoir, with followed rapid emptying to the minimum level. The complex hydraulic regime is formed in the body of the dam which forms the flood control reservoir during the flood, that is different from the operation of the water permanent reservoir. The design of the flood control structures is car-ried out in accordance with Ukrainian building codes for the construction of the water reservoirs with constant water level, and require testing the stability of the downstream slope for the maximum water levels under steady state seepage conditions and assessment the upstream slope stability during the water level decreasing  from the maximum level calculated in the steady state condition, these calculations do not correspond to the real seepage processes in the body of the dam of the dry flood control reservoir. Therefore, the purpose of this work is to determine the necessary boundary conditions of the flood control reservoir operation and upstream slope stability assessment by the limit equilibrium method. In the article the operation of the dry mountain flood control reservoir was analysed and found that the dam was characterized by two states: dry reservoir with water minimum water level and variable position of the seepage curve in the core and the upstream prism during the flood. The main factors influencing the upstream slope stability are the physical and mechanical properties of the soil, the laying of the slope, the period of time when the high-water level is maintained and the intensity of water level dropping. The upstream slope stability was evaluated by the Morgenstern & Price and Ordinary methods on the Slope/w software package. After the first 25 hours of the flood (period of high-water levels and the next water level dropping) the Safety Factor evaluated by limit equilibrium methods began to decrease, and reached the minimum value during the greatest seepage curve gradients at the time between 45 and 50 hours. Slope stability calculations by the limit equilibrium method were compared with the results of calculations performed by the SRM method, the values ​​of the Safety Factor and the way of their change during the flood evaluated by Ordinary and SRM methods almost coincide, which indicates the reliability of the results obtained by different methods of slope stability analysis

scholarly journals PERENCANAAN TUBUH BENDUNGANAIR LUAS KABUPATEN KAUR PROVINSI BENGKULU

2019 ◽  
Vol 9 (1) ◽  
pp. 23-37
Author(s):  
Robet Firmansyah ◽  
Besperi Besperi ◽  
Muhammad Fauzi
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
The Body ◽  
Rockfill Dam ◽  
Discharge Plan ◽  
Downstream Slope ◽  
Flow Filtration ◽  
The Stability ◽  
Base Elevation ◽  
Filtration Capacity

The purpose of this study was to plan the dimensions of the dam body that is technically feasible to build, as well as secure the stability. Flood discharge plan used amounted to 1,152 meters cubic/ sec with a return period of 1000 years. Based on the analysis that has been done, get a plan of flood water level is + 303,22 meters, surveillance obtained high of 3,0 meters, the body of the dam crest elevation gained + 306,22 meters high dam that is obtained by subtracting the height elevation of the peak body dam with a base elevation of the dam is 56,16 meters, width of the dam crest beacon of 11.0 meters, rockfill the upstream slope of 1:3 and for rockfill downstream slope is 1: 2,.25. Using the scheme of depression line formation with drainage leg with a graphic way, do not occur out of the body dam seepage and flow filtration capacity value of the calculation, Q = 9,553 x 10-5 meters cubic / sec, smallest than 2% Qinflow mean = 5,785 mmeters cubic / sec, dam secure against flow filtration. The stability of the main dam of landslide with the value of safety factor in a variety of conditions, namely dams both empty and fully charged in a normal state or an earthquake, for rockfill dam by calculating the weight of the dam, sliding moment, pore water pressure and earthquake loads. Using the method of slices Fellenius glide plane, the value obtained above safe rate (1,2), the planneddam safety to landslides

scholarly journals KAJIAN KERUSAKAN DAN KERUNTUHAN TUBUH BENDUNGAN AKIBAT PENGARUH BANJIR (STUDI KASUS : BENDUNGAN CIPAMINGKIS KAB. BOGOR)

2021 ◽  
Vol 14 (2) ◽  
pp. 113
Author(s):  
Heri Suherlan
Keyword(s):  
Land Use ◽  
Carrying Capacity ◽  
Rainy Season ◽  
Water Discharge ◽  
The Body ◽  
Rice Fields ◽  
The Impact ◽  
Damage Study

Land use in the vicinity of Cipamingkis Sub-watershed is currently very intensive, so that damage to land which is feared has an impact on the level of fertility and carrying capacity of the land, resulting in the danger of flooding, erosion and landslides in the rainy season, as well as a decrease in water discharge and lack of groundwater in the season dry. The impact of these conditions Cipamingkis Weir in Sukasirna Village, Jonggol District on April 20, 2017 there was a breakdown of the lighthouse and the body of the weir which was built since 1982, the dam irrigated 4579 Ha of rice fields, unable to irrigate and in the lower reaches of the dam a lot of damage, including: eroded riverbanks, damaged river cliffs, and part of the land cracked and landslides.Seeing the condition needs to be made a research on Cipamingkis Dam Damage Study. This handling is urgently needed to reduce and reduce the consequences caused in the process of activities that cause erosion and flooding.

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