scholarly journals The New Countermeasure SPAC against Seabed Scour due to Submerged Discharge and Large Waves

1991 ◽  
Vol 7 ◽  
pp. 301-306 ◽  
Author(s):  
Takao Shimizu ◽  
Akira Sasaki ◽  
Hisayosi Ujiie
Keyword(s):  
2015 ◽  
Vol 667 ◽  
pp. 444-448
Author(s):  
Zhuo Lin

Spool valves are the main elements in electro-hydro servo valves. Hydraulic measurement is an important method for spool valve’s null cutting measuring process. Because of the flow pattern transition, the discharge coefficient is a variable. This phenomenon causes errors if we assume the discharge coefficient is a constant as we always do. In this paper, the variable discharge coefficient is considered to the submerged discharge equation, and the flow pattern error is defined. For improving the precision of overlap values measurements, a compensation method of flow pattern error is presented in this paper.


2019 ◽  
Vol 21 (3) ◽  
pp. 474-492 ◽  
Author(s):  
Kiyoumars Roushangar ◽  
Ali Foroudi ◽  
Mojtaba Saneie

Abstract Ogee spillways with converging training walls are applied to lower the hazard of accidental flooding in locations with limited construction operations due to their unique structure. Hence, this type of structure is proposed as an emergency spillway. The present study aimed at experimental and machine learning-based modeling of the submerged discharge capacity of the converging ogee spillway. Two experimental models of Germi-Chay dam spillway were utilized: one model having a curve axis which was made in 1:50 scale and the other with a straight axis in 1:75 scale. Using visual observation, it was found that the total upstream head, the submergence degree, the ogee-crest geometries and the convergence angle of training walls are the crucial factors which alter the submerged discharge capacity of the converging ogee spillway. Furthermore, two machine-learning techniques (e.g. artificial neural networks and gene expression programming) were applied for modeling the submerged discharge capacity applying experimental data. These models were compared with four well-known traditional relationships with respect to their basic theoretical concept. The obtained results indicated that the length ratio () had the most effective role in estimating the submerged discharge capacity.


Author(s):  
Takao Shimizu ◽  
Masaaki Ikeno ◽  
Hisayoshi Ujiie ◽  
Kazuaki Yamauchi
Keyword(s):  

Polar Record ◽  
1992 ◽  
Vol 28 (165) ◽  
pp. 149-154 ◽  
Author(s):  
Steven F. Railsback

AbstractThe mixing characteristics of the existing surface wastewater discharge and a proposed submerged wastewater outfall at McMurdo Station, Antarctica, are compared. The wastewater is a combination of sanitary sewage and brine from a desalination plant. Dispersion from a proposed submerged (15 m-deep) outfall was simulated using the CORMIX1 computer model. The mixing characteristics of the surface discharge were estimated from visual observations and a conceptual analysis. The wastewater was found to be less dense than ambient seawater. From the submerged outfall, the effluent is predicted to be diluted by ratios ranging from 80:1 to 450:1 between the point of discharge and the point where the effluent plume begins to spread out underneath the sea ice. The variation in dilution depends mostly on tidal current speed, and dilution of the wastewater with desalinator brine is predicted to provide only minor reductions in concentrations of the effluent. The heat content of the discharge plume from a submerged outfall is expected to cause at least partial melting of the sea ice from underneath. A surface discharge provides much less mixing with ambient water before the effluent spreads along tidal cracks and underneath the sea ice. The submerged discharge is expected to confine settleable wastewater solids to a benthic area near the outfall, but a surface discharge allows solids to settle over a wider area.


1893 ◽  
Vol 37 (186) ◽  
pp. 903-909
Author(s):  
Captain G. Astuto
Keyword(s):  

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