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Issue Info: 
  • Year: 

    1395
  • Volume: 

    17
Measures: 
  • Views: 

    437
  • Downloads: 

    0
Keywords: 
Abstract: 

لطفا برای مشاهده چکیده به متن کامل (PDF) مراجعه فرمایید.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    16
  • Issue: 

    5 (SUPPLEMENT)
  • Pages: 

    129-139
Measures: 
  • Citations: 

    0
  • Views: 

    817
  • Downloads: 

    0
Abstract: 

Structures such as side orifices, side weirs, and side sluice gates are known as flow diversion structures among which side orifices have wide application in hydraulic and environmental Engineering. These flow diversion structures have been extensively used in irrigation and drainage networks, wastewater treatment plants, sedimentation tanks, etc. Therefore, Studying the pattern and characteristics of the flow -such as flow velocity components and free surface- adjacent to the side orifice would be important. In this paper, the flow over a sharp-crested rectangular side orifice in an open channel is simulated by FLOW-3D software. RNG k-e turbulence model is used to apply the Navier-Stokes equations and the VOF method is used to model the free surface profile changes. In the present study, the side orifice discharge and flow patterns are obtained by numerical simulation and are compared with experimental data of Hussian et al (2011) for model verification. The amount of the discharges through the orifice (both predicted by the present numerical simulation and recorded by the experimental research) are reported along with the relative errors which are about 8-9%. This shows relatively good agreement between numerical and experimental results. Therefore, the numerical model can be employed as a powerful tool for studying flow through side orifices in open channels.The effects of the side orifice crest's height (H) on the flow velocity components and free surface adjacent to the side orifice are also investigated. Results indicate that the discharge ratio (ratio of the discharge through the side orifice to the inlet discharge of the main channel) is increased with decreasing the height of the side orifice crest. Maximum and minimum values for longitudinal component of the velocity -for all heights of the side orifice crest- is reported at the beginning and end of the side orifice, respectively. By decreasing the height of the side orifice crest, these maximum and minimum values are respectively increased and decreased. Decreasing the height of the side orifice crest, the longitudinal component of the velocity in the vicinity of the side orifice is negative because of the reverse flow formed in this area. Examining the variation of lateral velocity component shows that this component is increased with decreasing the height of orifice crest. That is why the amount of discharge through the side orifice is increased with decreasing the height of orifice crest.The flow direction is upward at the height level of 0.25H; therefore, vertical component of velocity trough the orifice length is positive in all cases. On the other hand, the flow direction is downward at the height level 0.75H; thus, vertical component of velocity trough the orifice length is negative in all cases. Absolute value of the vertical velocity is increased by decreasing the height of the side orifice crest (H) because more flow is diverted to the side orifice. By increasing the height of orifice crest significant changes are reported in the free surface profiles especially in the vicinity of the side orifice.

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Issue Info: 
  • Year: 

    2023
  • Volume: 

    55
  • Issue: 

    2
  • Pages: 

    319-336
Measures: 
  • Citations: 

    0
  • Views: 

    79
  • Downloads: 

    17
Abstract: 

Using the control tools is an efficient method to decrease the responses of the structure under external excitations. In this regard, this study investigates the performance of two structures equipped with MR dampers and Orifice dampers under blast-induced vibration. In addition to stimulating the underground blast-induced vibration (due to the different nature of these loads), seismic excitation has also been used to evaluate the efficiency of these dampers. These dampers are semi-active devices, which change the output force of the damper by changing the input voltage and magnetic field of dampers. Also, in this paper, clipped-optimal algorithm was used. This algorithm can generate optimal damper force by changing the voltage at each time step based on the input forces. In this research, structural responses based on optimal and maximum voltage are considered. Also, the numerical results of the structure are compared with LQR algorithm. The LQR algorithm is considered a criterion for reducing structural responses to blast-induced vibration. The results indicate that the proposed method (the different locations and types of dampers) is efficient for decreasing the responses of the structure.

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Author(s): 

اسلیمن پ.

Issue Info: 
  • Year: 

    1384
  • Volume: 

    -
  • Issue: 

    2
  • Pages: 

    43-44
Measures: 
  • Citations: 

    2
  • Views: 

    278
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 278

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Journal: 

Issue Info: 
  • Year: 

    2003
  • Volume: 

    16
  • Issue: 

    1 (58 IN NATURAL RESOURCES)
  • Pages: 

    47-55
Measures: 
  • Citations: 

    0
  • Views: 

    2474
  • Downloads: 

    0
Abstract: 

Submerged rectangular orifice is among discharge measuring device which is suitable in small canal especially when the amount of fallis not adequat for application of weir, during the past decade many study have been conducted for evaluation of discharge coefficient of orifice. For free the case of submerged orifice only an average value of 0.61 has been mentiond in the literature. Since this coefficient depends to the flow characteristics and the orifice dimensions, an equation for determination of discharge coefficient is needed. The development of such formula is the main goal of this study. To do so an experimental program was conducted and applying the dimensional analysis and data obtained from these tests, one relation was developed. This relation can be used where an accurate value of the discharge coefficient and consequently the flow discharge is needed.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Journal: 

Issue Info: 
  • Year: 

    2002
  • Volume: 

    15
  • Issue: 

    2 (55 IN NATURAL RESOURCES)
  • Pages: 

    64-72
Measures: 
  • Citations: 

    0
  • Views: 

    798
  • Downloads: 

    0
Abstract: 

Filling of locks in low lifts, generally accomplish by slots in gates and energy of flow dissipates by stilling basin and baffles. In this new system gate has been designed in the form of box and openings are made in two, upstream (U/S) and downstream (D/S) walls and flow control is done by these gates. This system includes a few orifices in U/S and some under sluice in D/S. Some laboratory tests have been done for determining discharge coefficient (Cd). Results show that (Cd) for this system is different from (Cd) for orifices and sluice gates. Generally the latter (Cd) is lower than the former. This is due to difference in orifice edges and hydraulic loss between two walls. An equation has been developed in this research for multi dabble orifices.

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Author(s): 

MCHENRY M.A.

Issue Info: 
  • Year: 

    2002
  • Volume: 

    10
  • Issue: 

    4
  • Pages: 

    299-305
Measures: 
  • Citations: 

    1
  • Views: 

    165
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 165

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Author(s): 

Journal: 

UPDATES IN SURGERY

Issue Info: 
  • Year: 

    2023
  • Volume: 

    75
  • Issue: 

    1
  • Pages: 

    197-203
Measures: 
  • Citations: 

    1
  • Views: 

    3
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Journal: 

PLANT PROTECTION

Issue Info: 
  • Year: 

    2016
  • Volume: 

    39
  • Issue: 

    3
  • Pages: 

    173-185
Measures: 
  • Citations: 

    0
  • Views: 

    233
  • Downloads: 

    0
Abstract: 

In this article, downstream scour patterns were investigated for submerged jets with different diameters and shapes (circular, rectangle, diamond and square) for single jets and also effects of different angles of crossing compound jets. For this aim, all effective parameters of submerged jets behavior were studied and the effective dimensionless relationships were derived according to dimensional analysis. In order to analyze this relationship, a physical model was built in KWPA laboratory and tests were run with different discharges. Then dimensions of scour patterns were measured in downstream of jets. The results indicated that the best development in pattern of scour belongs to diamond jet with average of 22% increasing in comparison by rectangle jet and the minimum of outer diameter with average of 183% increasing in comparison by the maximum one, also threefold increasing of crossing jets angles cause 58% increasing in the parameters of scour.

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Issue Info: 
  • Year: 

    2012
  • Volume: 

    22
  • Issue: 

    96
  • Pages: 

    0-0
Measures: 
  • Citations: 

    0
  • Views: 

    1705
  • Downloads: 

    0
Abstract: 

Double orifice mitral valve (DOMV) is an uncommon anomaly that was first described by Greenfield. Since then more than 200 cases have been reported. In this anomaly, mitral valve has a single fibrous annulus which opens with two openings into the left ventricle. We report a case of DOMV accompanied with severe stenosis in a 22-year old female who had complaints of moderate dyspnea. In transthoracic echo cardiography, mitral valve had two orifices which were supported by their chordate and papillary muscles. Color Doppler echo revealed severe mitral stenosis but no other congenital anomaly was demonstrated. Transthoracic echocardiography (TTE) and trans esophageal echocardiography (TEE) are useful methods for determining anatomical and functional aspects of the mitral apparatus in this congenital disease.

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