scholarly journals Numerical modelling of study the effect of the entrainment velocity, the number of Nusselt and the thickness of the non-convective zone on the stability of the pond solar

2021 ◽  
pp. 1-16
Author(s):  
Sabrina GHERAİBİA ◽  
Amar GUESMIA
Keyword(s):  
Numerical Modelling ◽  
Convective Zone ◽  
Entrainment Velocity ◽  
The Stability

Assessing the Maximum Stability of the Nonconvective Zone in a Salinity-Gradient Solar Pond

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
A. A. Abdullah ◽  
K. A. Lindsay
Keyword(s):  
Salinity Gradient ◽  
Fluid Velocity ◽  
Weather Conditions ◽  
Convective Zone ◽  
Heat Extraction ◽  
Solar Pond ◽  
Maximum Stability ◽  
Storage Zone ◽  
The Stability

The quality of the stability of the nonconvective zone of a salinity-gradient solar pond (SGSP) is investigated for an operating protocol in which the flushing procedure exactly compensates for evaporation losses from the solar pond and its associated evaporation pond. The mathematical model of the pond uses simplified, but accurate, constitutive expressions for the physical properties of aqueous sodium chloride. Also, realistic boundary conditions are used for the behaviors of the upper and lower convective zones (LCZs). The performance of a salinity-gradient solar pond is investigated in the context of the weather conditions at Makkah, Saudi Arabia, for several thickness of upper convective zone (UCZ) and operating temperature of the storage zone. Spectral collocation based on Chebyshev polynomials is used to assess the quality of the stability of the pond throughout the year in terms of the time scale for the restoration of disturbances in temperature, salinity, and fluid velocity underlying the critical eigenstate. The critical eigenvalue is found to be real and negative at all times of year indicating that the steady-state configuration of the pond is always stable, and suggesting that stationary instability would be the anticipated mechanism of instability. Annual profiles of surface temperature, salinity, and heat extraction are constructed for various combinations for the thickness of the upper convective zone and storage zone temperature.

Numerical modelling of rainfall effects on the stability of soil slopes

2017 ◽  
Vol 13 (5) ◽  
pp. 425-437 ◽  
Author(s):  
Adarsh S. Chatra ◽  
G. R. Dodagoudar ◽  
V. B. Maji
Keyword(s):  
Numerical Modelling ◽  
Soil Slopes ◽  
The Stability

scholarly journals Field and Numerical Modelling Investigations on the Stability of Underground Strata during Longwall Workings

2021 ◽  
Author(s):  
G Budi ◽  
Kolikipogu Nageswara Rao ◽  
Punit Mohanty
Keyword(s):  
Numerical Modelling ◽  
Longwall Mining ◽  
High Capacity ◽  
Field Monitoring ◽  
Longwall Face ◽  
Mining Method ◽  
Company Limited ◽  
Extensive Field ◽  
Powered Support ◽  
The Stability

Abstract Understanding the behaviour of underground workings is essential for the success of any mining method. The longwall mining method is one of the predominant underground methods to extract coal. Since 1978, in India, 22 underground coal mines of different collieries have been implemented the mechanized longwall method. SCCL is one of that colliery has mixed working experiences with longwall method in their mines. The longwall faces in GDK-10A, JK-5, and VK-7 of SCCL had produced good results, but the faces in GDK-7, GDK-9, GDK-11A, and PVK-5 had suffered due to the geological disturbances and unavailability of real-time information about the strata behaviour. By addressing the previous experiences of longwall workings, Singareni Collieries Company Limited (SCCL) has implemented a high capacity (1 × 1152T) powered support system in Adriyala Longwall Project (ALP) at a depth of 375m. In this study, extensive field monitoring with different strata monitoring instruments was conducted in ALP to analyze the gate roads convergence, stress variation on longwall and chain pillars at different stages of extraction (i.e., 8m, 25m, 35m, and 45m) and the pressure variation on the powered support systems. It was observed from the results that the convergence in the gate roads was increasing with the advance of the longwall face and the area of exposure. The pressure of the legs on the dip side was less than the pressure of the legs on the rise side, which implies a stable roof condition over the longwall face. To better understand the behaviour of ALP workings, a numerical modelling study with FLAC 7.0 has been conducted with actual physio-mechanical properties. The computed numerical modelling results have been remarkably well in consistent with the field monitoring results. The stability of chain pillars has been estimated at every stage of extraction by the Factor of Safety (FoS) criterion and it was found that the pillars could be ensured stability in longwall workings.

scholarly journals Use of Geogrids and Recycled Rubber in Railroad Infrastructure for Enhanced Performance

Geosciences ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 30 ◽  
Author(s):  
Buddhima Indraratna ◽  
Yujie Qi ◽  
Trung Ngoc Ngo ◽  
Cholachat Rujikiatkamjorn ◽  
Tim Neville ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Ground Improvement ◽  
Test Results ◽  
Track Maintenance ◽  
Work Input ◽  
The Stability ◽  
Absorbing Property ◽  
Energy Absorbing ◽  
The University ◽  
Track Deformation

Railway tracks are conventionally built on compacted ballast and structural fill layers placed above the natural (subgrade) foundation. However, during train operations, track deteriorations occur progressively due to ballast degradation. The associated track deformation is usually accompanied by a reduction in both load bearing capacity and drainage, apart from imposing frequent track maintenance. Suitable ground improvement techniques involving plastic inclusions (e.g., geogrids) and energy absorbing materials (e.g., rubber products) to enhance the stability and longevity of tracks have become increasingly popular. This paper presents the outcomes from innovative research and development measures into the use of plastic and rubber elements in rail tracks undertaken at the University of Wollongong, Australia, over the past twenty years. The results obtained from laboratory tests, mathematical modelling and numerical modelling reveal that track performance can be improved significantly by using geogrid and energy absorbing rubber products (e.g., rubber crumbs, waste tire-cell and rubber mats). Test results show that the addition of rubber materials can efficiently improve the energy absorption of the structural layer and also reduce ballast breakage. Furthermore, by incorporating the work input parameters, the energy absorbing property of the newly developed synthetic capping layer is captured by correct modelling of dilatancy. In addition, the laboratory behavior of tire cells and geogrids has been validated by numerical modelling (i.e., Finite Element Modelling-FEM, Discrete Element—DEM), and a coupled DEM-FEM modelling approach is also introduced to simulate ballast deformation.

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