Non-Darcy effects in fracture flows of a yield stress fluid

2016 ◽  
Vol 805 ◽  
pp. 222-261 ◽  
Author(s):  
A. Roustaei ◽  
T. Chevalier ◽  
L. Talon ◽  
I. A. Frigaard
Keyword(s):  
Pressure Gradient ◽  
Yield Stress ◽  
Single Phase ◽  
Stokes Problem ◽  
Type Flow ◽  
New Type ◽  
Approximate Expressions ◽  
Limiting Pressure Gradient ◽  
Selection Of ◽  
Limiting Pressure

We study non-inertial flows of single-phase yield stress fluids along uneven/rough-walled channels, e.g. approximating a fracture, with two main objectives. First, we re-examine the usual approaches to providing a (nonlinear) Darcy-type flow law and show that significant errors arise due to self-selection of the flowing region/fouling of the walls. This is a new type of non-Darcy effect not previously explored in depth. Second, we study the details of flow as the limiting pressure gradient is approached, deriving approximate expressions for the limiting pressure gradient valid over a range of different geometries. Our approach is computational, solving the two-dimensional Stokes problem along the fracture, then upscaling. The computations also reveal interesting features of the flow for more complex fracture geometries, providing hints about how to extend Darcy-type approaches effectively.

About the Selection of a Single-Phase Short-Circuit Current on Earth in the Network With Low-Ohm Resistive Grounding of the Neutral

2017 ◽  
pp. 34-41
Author(s):  
Andrei V. MAIOROV ◽  
◽  
Kirill A. OSINTSEV ◽  
Andrei V. SHUNTOV ◽  
◽  
...  
Keyword(s):  
Single Phase ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Selection Of

Selection of worm species and packing in a new type of biologic reactor for sludge reduction

2014 ◽  
Author(s):  
S.X. Li ◽  
Z.H. Wang ◽  
D.M. Li ◽  
W.W. Duan ◽  
S. Mei ◽  
...  
Keyword(s):  
Sludge Reduction ◽  
New Type ◽  
Selection Of

ON THE SELECTION OF CORRELATIONS FOR A PRESSURE GRADIENT CALCULATION (ON THE EXAMPLE OF SAMARA AND ORENBURG REGIONS)

2020 ◽  
pp. 26-31
Author(s):  
V.P. Shakshin ◽  
◽  
A.A. Mokrev ◽  
V.S. Vasil’ev ◽  
S.A. Belov ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Gradient Calculation ◽  
Selection Of

scholarly journals Development of KASP Markers for Germplasm Characterization and Fingerprinting Identification of Broccoli in China

2020 ◽  
Author(s):  
Yusen Shen ◽  
Jiansheng Wang ◽  
Huifang Yu ◽  
Xiaoguang Sheng ◽  
Zhenqing Zhao ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Marker Assisted Selection ◽  
Genetic Relationships ◽  
Cost Effective ◽  
Germplasm Characterization ◽  
2D Barcode ◽  
New Type ◽  
Generation Sequencing ◽  
Kasp Markers ◽  
Selection Of

Abstract Background: Broccoli (Brassica oleracea var. italica) is a vegetable widely cultivated in China. Many new-type broccoli cultivars were bred and developed by Chinese breeders during the recent three decades. However, the broccoli cultivar nomenclature and detailed information of genetic relationships among broccoli germplasms are unclear. Results: The present study identified millions of SNPs by next-generation sequencing of 23 representative broccoli lines. Through several steps of selection, 100 SNPs were successfully converted into KASP markers, and used to evaluate the genetic diversity, genetic relationship, and population structure of 392 broccoli accessions, which represent the mainly broccoli breeding materials in China. The initial, introduced and improved accessions were well clustered, though some accessions were overlapped between groups, probably reflecting the fact that breeding activities led to genetic similarities. To make the KASP genotyping more efficient and cost-effective, 25 of the 100 KASPs were selected for fingerprinting of all accessions, and the 2D barcode contained fingerprinting information were generated for elite varieties. Conclusion: The KASP markers developed in this study provided an efficient way for germplasm characterization, DNA fingerprinting, seed purity identification, and marker-assisted selection of broccoli in China.

scholarly journals Modeling Features of a Single Phase-to-Earth Fault in a Medium Voltage Overhead Transmission Line

2020 ◽  
Vol 4 (2) ◽  
pp. 127-138
Author(s):  
Ismael Saeed ◽  
Kamal Sheikhyounis
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Single Phase ◽  
Single Frequency ◽  
Mathematical Representation ◽  
Medium Voltage ◽  
Overhead Transmission Line ◽  
Earth Fault ◽  
Distributed Parameters ◽  
Selection Of

The modeling and calculation of a single phase-to-earth fault of 6 to 35 kV have specific features when compared with circuits with higher nominal voltages. In this paper, a mathematical analysis and modeling of a 3-phase overhead transmission line with distributed parameters consisting of several nominal T-shaped, 3-phase links with concentrated parameters replaced by 1 nominal T-shaped link were carried out. Further analysis showed that not accounting for the distributed nature of the line parameters did not cause significant errors in the assessment of the maximum overvoltage in the arc suppression in single phase-to-earth faults, and that sufficient accuracy insures the representation of the line by only 1 nominal T-shaped, 3-phase link. Such a modeling technique makes it impossible to identify the location of single-phase faults, which is the property of higher harmonic amplification of individual frequencies. Chain equivalent schemas with constant parameters are valid for a single frequency, thereby providing an opportunity to study the nature of the wave process by the discrete selection of parameters. Next in the mathematical representation, we consider the overhead transmission lines as lines with distributed parameters.

scholarly journals Voltages Induced in Overhead Ground-Wire Cable as Risk Factor. Part 1

2016 ◽  
Vol 5 (1) ◽  
pp. 28-40 ◽  
Author(s):  
Токарский ◽  
A. Tokarskiy ◽  
Рубцова ◽  
Nina Rubtsova ◽  
Рябченко ◽  
...  
Keyword(s):  
Risk Factor ◽  
Single Phase ◽  
Interval Length ◽  
Maximum Permissible Level ◽  
Overhead Transmission Line ◽  
Spark Gap ◽  
Three Phase ◽  
Electric And Magnetic Fields ◽  
Short Circuits ◽  
Selection Of

To ensure the staff safety under hot-line overhead transmission line (OTL) maintenance, as well as overhead ground-wire cable (OGWC) insulation integrity maintaining, by the example of three-phase 750 kV OTL has been presented an algorithm for calculation of voltages and electromotive forces (EMF) induced in this line’s OGWC by electric and magnetic fields (EF and MF) generated by OTL phases’ voltages and currents. Algorithms for calculation of line-to-earth voltages distribution along grounded at one end OGWC’ intervals have been given. It has been shown that the voltage induced at OGWC by EF of 750 kV OTL is much less than the voltage induced by this OTL’s MF. For single-phase short circuits modes has been presented an algorithm for selection of grounded at one end OGWC’ interval length by condition of respecting of voltage’s maximum permissible level on a spark gap shunting OGWC’s insulator set.

scholarly journals FEATURES OF MODELING THE DRIVE UNIT OF THE MIXER WITH BIDIRECTIONAL ROTATIONAL IMPACT ON THE MATERIAL

2020 ◽  
pp. 101-107
Author(s):  
K. Yudin ◽  
A. Pogosbekov
Keyword(s):  
Static Analysis ◽  
Frequency Converter ◽  
Practical Implementation ◽  
Belt Drive ◽  
Unit Operation ◽  
The Finite Element Method ◽  
Drive Unit ◽  
Mixing Chamber ◽  
New Type ◽  
Selection Of

Periodical mixers are considered. The expediency of developing a new type of mixer is presented. Features of the material movement in the mixer allow to speak about the presence of elements of a gyroscopic effect. The mixing chamber is rotated by means of belt, chain and conical transmission. The resulting complex spatial movement of material particles can be controlled by a frequency Converter and the selection of appropriate gears or using a belt drive. An algorithm for modeling the drive unit of a mixer with a bidirectional rotational effect on the material is presented. The features of the drive unit and its components are considered. The task is to build a model of deformation of the drive unit of the mixer. The finite element method (FEM) for the drive unit of the mixer is used. Machine experiments are performed that implement fatigue calculations of the drive unit with a study in the SolidWorks Simulation environment. The results of static analysis of the drive unit operation in determining the deformation, static analysis of the drive unit operation in determining the voltage with varying torque are obtained. A variant of static analysis is presented when using a belt drive instead of a gear drive. The practical implementation of the mixer drive unit in metal is shown. Conclusions on modeling are made.

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