scholarly journals Upscaling of Permeability Field of Fractured Rock System: Numerical Examples

2012 ◽  
Vol 2012 ◽  
pp. 1-20 ◽  
Author(s):  
Kai Bao ◽  
Amgad Salama ◽  
Shuyu Sun
Keyword(s):  
Effective Permeability ◽  
Fractured Rock ◽  
Complex Permeability ◽  
Coarse Mesh ◽  
Rock System ◽  
Numerical Examples ◽  
Fine Mesh ◽  
Exit Boundary ◽  
Permeability Field ◽  
Good Agreement

When the permeability field of a given porous medium domain is heterogeneous by the existence of randomly distributed fractures such that numerical investigation becomes cumbersome, another level of upscaling may be required. That is such complex permeability field could be relaxed (i.e., smoothed) by constructing an effective permeability field. The effective permeability field is an approximation to the real permeability field that preserves certain quantities and provides an overall acceptable description of the flow field. In this work, the effective permeability for a fractured rock system is obtained for different coarsening scenarios starting from very coarse mesh all the way towards the fine mesh simulation. In all these scenarios, the effective permeability as well as the pressure at each cell is obtained. The total flux at the exit boundary is calculated in all these cases, and very good agreement is obtained.

scholarly journals Effect of Mesh Topologies to Predict Cooling Effect on Evaporative Cooling Duct

2021 ◽  
Vol 2111 (1) ◽  
pp. 012012
Author(s):  
A Jamaldi ◽  
Sarjito ◽  
A S Nurrohkayati ◽  
N T Atmoko
Keyword(s):  
Numerical Study ◽  
Evaporative Cooling ◽  
Temperature Drop ◽  
Coarse Mesh ◽  
Simulation Process ◽  
Fine Mesh ◽  
Airflow Distribution ◽  
Different Levels ◽  
Good Agreement

Abstract This paper examines the effect of different mesh types on a numerical study of evaporative cooling in the chimney. This research is a follow-up study from previous research. The test specimen used is an evaporative chimney design with the addition of a nozzle arrangement in it. The main focus of this research is the study of mesh refinement, namely by applying structured mesh during the simulation process. Three types of mesh with different levels of fineness were used for the specimens. They are coarse ( mesh A), medium (mesh B), and fine (mesh C). In addition to differences in mesh, research was also carried out with variations in the level of relative humidity (RH). The RH levels used are 5, 10, and 15%. Two main parameters of evaporative cooling performance are airflow distribution and temperature drop in the chimney. Method for measuring the distribution of airflow and temperature drop in the chimney by making five planes with different heights. The results showed that the simulation with mesh B produced a good agreement data with previous studies than mesh A and C. The RH level that generated the most optimal cooling is found at 5% RH.

Theoretical Assessment of Compressibility Factor of Gases by Using Second Virial Coefficient

2018 ◽  
Vol 73 (2) ◽  
pp. 121-125
Author(s):  
Bahtiyar A. Mamedov ◽  
Elif Somuncu ◽  
Iskender M. Askerov
Keyword(s):  
Virial Coefficient ◽  
Second Virial Coefficient ◽  
Compressibility Factor ◽  
Analytical Approximation ◽  
Accurate Evaluation ◽  
Numerical Examples ◽  
Lennard Jones ◽  
Theoretical Assessment ◽  
Good Agreement

AbstractWe present a new analytical approximation for determining the compressibility factor of real gases at various temperature values. This algorithm is suitable for the accurate evaluation of the compressibility factor using the second virial coefficient with a Lennard–Jones (12-6) potential. Numerical examples are presented for the gases H2, N2, He, CO2, CH4 and air, and the results are compared with other studies in the literature. Our results showed good agreement with the data in the literature. The consistency of the results demonstrates the effectiveness of our analytical approximation for real gases.

Modeling of Multibody Flexible Articulated Structures With Mutually Coupled Motions: Part II — Application and Results

1992 ◽  
Author(s):  
Jiechi Xu ◽  
Joseph R. Baumgarten
Keyword(s):  
Experimental Data ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Open Loop ◽  
Body Motion ◽  
Universal Joint ◽  
Open Loop System ◽  
Numerical Examples ◽  
Kinematic Properties ◽  
Good Agreement

Abstract The application of the systematic procedures in the derivation of the equations of motion proposed in Part I of this work is demonstrated and implemented in detail. The equations of motion for each subsystem are derived individually and are assembled under the concept of compatibility between the local kinematic properties of the elastic degrees of freedom of those connected elastic members. The specific structure under consideration is characterized as an open loop system with spherical unconstrained chains being capable of rotating about a Hooke’s or universal joint. The rigid body motion, due to two unknown rotations, and the elastic degrees of freedom are mutually coupled and influence each other. The traditional motion superposition approach is no longer applicable herein. Numerical examples for several cases are presented. These simulations are compared with the experimental data and good agreement is indicated.

scholarly journals An Adaptive Approach to Solutions of Fredholm Integral Equations of the Second Kind

2014 ◽  
Vol 2014 ◽  
pp. 1-13
Author(s):  
Nebiye Korkmaz ◽  
Zekeriya Güney
Keyword(s):  
Galerkin Method ◽  
Integral Equations ◽  
Iteration Method ◽  
Legendre Polynomials ◽  
Optimization Problem ◽  
Approximate Solutions ◽  
Basis Functions ◽  
Fredholm Integral Equations ◽  
Coarse Mesh ◽  
Fine Mesh

As an approach to approximate solutions of Fredholm integral equations of the second kind, adaptive hp-refinement is used firstly together with Galerkin method and with Sloan iteration method which is applied to Galerkin method solution. The linear hat functions and modified integrated Legendre polynomials are used as basis functions for the approximations. The most appropriate refinement is determined by an optimization problem given by Demkowicz, 2007. During the calculationsL2-projections of approximate solutions on four different meshes which could occur between coarse mesh and fine mesh are calculated. Depending on the error values, these procedures could be repeated consecutively or different meshes could be used in order to decrease the error values.

scholarly journals Detecting radiolaria in the field

1991 ◽  
Vol 10 (1) ◽  
pp. 22-22 ◽  
Author(s):  
Simon K. Haslett ◽  
Paul D. Robinson
Keyword(s):  
Rock Type ◽  
Fine Fraction ◽  
Field Work ◽  
Coarse Mesh ◽  
Extraction Techniques ◽  
The Past ◽  
Fine Mesh ◽  
Rock Types ◽  
Siliceous Rock ◽  
Calcareous Microfossils

Abstract. Radiolaria can be preserved in all types of marine sedimentary rocks, the method for their extraction being dependent on the mineralogy of the radiolarian test and the nature of the rock-type in which they occur. In the past radiolaria could only be viewed in thin section (Hinde, 1890; Hinde & Fox, 1895), with no method of detecting the presence of radiolaria prior to sectioning. Modern extraction techniques are normally laboratory based and use hazardous chemicals, therefore it is advantageous to establish the radiolarian content of the sample before collection and transportation back to the laboratory. This can be achieved in a number of ways:-1. Non-lithified sediments. Radiolaria are separated from the sediment by washing the sample over a set of small sieves. Two mesh sizes should be used, a coarse mesh around 150μm to separate large litho-fragments, and a fine mesh no greater than 63μm to concentrate the radiolaria. The fine fraction is then washed with dilute hydrochloric acid (HCl) to eliminate the calcareous microfossils, leaving a pure radiolarian sludge, which is dried on filter paper.2. Siliceous rock-types. Methods for extracting radiolaria from cherts have been in use since the early 1970’s (Dumitrica, 1970; Pessagno & Newport, 1972), and have recently been applied to field-work (Cordey & Krauss, 1990). The recognition of fossiliferous bedded cherts is possible with the use of a hand-lens in good sunlight. If radiolaria are present, they should be detectable as small protrusions, especially along laminae. To extract the radiolaria, break up the sample. . .

scholarly journals Turbulence generation from a stochastic wavelet model

2018 ◽  
Vol 474 (2217) ◽  
pp. 20180093
Author(s):  
Y. Du ◽  
G. Lin
Keyword(s):  
Input Data ◽  
Computation Cost ◽  
Fourier Methods ◽  
Numerical Examples ◽  
Scale Reduction ◽  
Inhomogeneous Turbulence ◽  
Comparable Accuracy ◽  
Turbulence Generation ◽  
Theoretical Results ◽  
Good Agreement

This research presents a new turbulence generation method based on stochastic wavelets and tests various properties of the generated turbulence field in both the homogeneous and inhomogeneous cases. Numerical results indicate that turbulence fields can be generated with much smaller bases in comparison to synthetic Fourier methods while maintaining comparable accuracy. Adaptive generation of inhomogeneous turbulence is achieved by a scale reduction algorithm, which greatly reduces the computation cost and practically introduces no error. The generating formula issued in this research could be adjusted to generate fully inhomogeneous and anisotropic turbulence with given RANS data under divergence-free constraint, which was not achieved previously in similar research. Numerical examples shows that the generated homogeneous and inhomogeneous turbulence are in good agreement with the input data and theoretical results.

Post-Test Investigations of BFBT Critical Power Tests With Trace

2009 ◽  
Author(s):  
Marc Thieme ◽  
Wolfgang Tietsch ◽  
Rafael Macian ◽  
Victor Hugo Sanchez Espinoza
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Critical Power ◽  
The Core ◽  
Fine Mesh ◽  
The Us ◽  
Post Test ◽  
Trace Model ◽  
Good Agreement ◽  
Transfer Models

The validation of heat transfer models of safety analysis codes such as TRACE is very important due to the strong interaction of the thermal hydraulics parameters with the core neutronics. TRACE is the reference system code of the US NRC for LWR. It is being developed and extensively validated within the international CAMP-program. In this paper, the validation of heat transfer models of TRACE related to the prediction of the critical power is presented. The validation is based on a large number of critical power tests performed in the NUPEC BFBT (BWR Full-Size Fine-Mesh Bundle Tests) facility in Japan. These tests were analysed with the TRACE Version 5 RC 2. The comparison of predictions with the experimental data shows good agreement. The developed TRACE model and the comparison of experimental data with code results will be presented and discussed.

Modelling and Simulation of Temperature and Stress Analysis in TIG Welding Process

2015 ◽  
Vol 830-831 ◽  
pp. 294-297
Author(s):  
Nayan Chandak ◽  
Mohan Kumar Pradhan ◽  
Lokesh Boriwal
Keyword(s):  
Residual Stress ◽  
Structural Analysis ◽  
Strain State ◽  
Processing Time ◽  
Welding Process ◽  
Time Interval ◽  
Coarse Mesh ◽  
Ansys Software ◽  
Fine Mesh ◽  
Material Conditions

In this study, the welding process is modelled and analysed using ANSYS software. The temperature and residual stress produced during the process is depicted. During heating, the material conditions, parts affected by residual stress and the stress–strain state at different time interval is recorded and a subsequent structural analysis is used for the analysis, the same is used in the analysis where thermal and structural results are investigated. Subsequently, with sensitivity analysis the results are evaluated. Non-uniform meshing is used to entrap the result with fine mesh in the heat affected zone and coarse mesh away from it to save processing time. The results from the thermal structural analysis are presented to understand the process deeply and comparison of the graph plot between temperature and time is explained.

Simulation of the Diameters, Length and Content Effect on the Magnetic Properties of Glass-Coated Magnetic Alloy Microwires

2012 ◽  
Vol 229-231 ◽  
pp. 117-120
Author(s):  
Ze Yi Sun ◽  
Yong Jiang Di ◽  
Zhi Qiang Zhong
Keyword(s):  
Effective Permeability ◽  
Resonance Peak ◽  
Complex Permeability ◽  
Magnetic Alloy ◽  
Intrinsic Permeability ◽  
Frequency Increase ◽  
Apparent Permeability ◽  
Magnetic Resonance Frequency ◽  
Microwave Permeability ◽  
The Wire

The microwave permeability of glass-coated magnetic alloy microwires / dielectric composite was investigated by apparent permeability linked with intrinsic permeability calculated based on Landau-Lifshitz function. The effect of diameter, length and microwires content on the composite effective permeability was simulated. The simulated results show that the complex permeability decreases with the increase of the microwires diameter and the wire content in the composite. The microwave magnetic resonance frequency increase distinctly with the lengthening of the glass-coated microwires. The full width at half maximum of the ferromagnetic resonance peak increases with the lengthening of the microwires and the decrease of the wire content.

Conidium production from leaves and needles in four streams

1982 ◽  
Vol 60 (8) ◽  
pp. 1487-1494 ◽  
Author(s):  
Felix Bärlocher
Keyword(s):  
Coniferous Forest ◽  
Hard Water ◽  
Experimental Period ◽  
Unit Weight ◽  
Coarse Mesh ◽  
Black Forest ◽  
Additional Species ◽  
Conidium Production ◽  
Fine Mesh ◽  
Forest Streams

Oak leaves and larch and spruce needles in fine-mesh (0.3 mm) and coarse-mesh (3 mm) bags were exposed in two hard-water streams in the Swiss Jura and two soft-water streams in the Black Forest. Periodically, conidium production in samples was determined under defined conditions. Generally, conidium production per unit weight was highest in oak, followed by larch and spruce. In oak and larch, an early peak was followed by a gradual decline; in spruce, conidium production reached an early plateau in the Jura streams but increased throughout the experimental period in the Black Forest streams. Percentage similarity between substrate spora and stream spora was highest for oak, followed by larch and spruce in three of the streams with deciduous riparian vegetation. The reverse sequence occurred in the remaining stream of a coniferous forest. On oak and larch, more fungal species were recovered in fine-mesh than in coarse-mesh bags; however, these additional species were numerically unimportant. Heliscus lugdunensis was the dominant species in early stages of spruce decay. It was replaced at later stages by Alatospora acuminata in the Jura streams and by two other species in the Black Forest streams. On oak and larch, the four or five most common species remained dominant throughout the experimental period.

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