Efficient Methods for Numerical Modeling of Laminar Friction in Fluid Lines

2006 ◽  
Vol 128 (4) ◽  
pp. 829-834 ◽  
Author(s):  
D. Nigel Johnston
Keyword(s):  
Computational Efficiency ◽  
Method Of Characteristics ◽  
High Accuracy ◽  
Slight Reduction ◽  
Improved Method ◽  
Frequency Dependent ◽  
Transmission Line Method ◽  
Laminar Pipe Flow ◽  
Very High ◽  
High Computational Efficiency

An improved method for simulating frequency-dependent friction in laminar pipe flow using the method of characteristics is proposed. It has a higher computational efficiency than previous methods while retaining a high accuracy. By lumping the frequency-dependent friction at the ends of the pipeline, the computational efficiency can be improved further, at the expense of a slight reduction in accuracy. The technique is also applied to the transmission line method and found to give a significant improvement in accuracy over previous methods, while retaining a very high computational efficiency.

Efficient Methods for Numerical Modelling of Laminar Friction in Fluid Lines

2004 ◽  
Author(s):  
D. Nigel Johnston
Keyword(s):  
Computational Efficiency ◽  
Method Of Characteristics ◽  
High Accuracy ◽  
Slight Reduction ◽  
Improved Method ◽  
Frequency Dependent ◽  
Transmission Line Method ◽  
Laminar Pipe Flow ◽  
Very High ◽  
High Computational Efficiency

An improved method for simulating frequency-dependent friction in laminar pipe flow using the Method of Characteristics (MOC) is proposed. It has a higher computational efficiency than previous methods whilst retaining a high accuracy. By lumping the frequency-dependent friction at the ends of the pipeline the computational efficiency can be improved further, at the expense of a slight reduction in accuracy. The technique is also applied to the Transmission Line Method (TLM) and found to give a significant improvement in accuracy over previous methods, whilst retaining a very high computational efficiency.

scholarly journals Frequency-Dependent Friction in Transient Pipe Flow

1968 ◽  
Vol 90 (1) ◽  
pp. 109-115 ◽  
Author(s):  
W. Zielke
Keyword(s):  
Pipe Flow ◽  
Response Curve ◽  
Method Of Characteristics ◽  
Mean Velocity ◽  
Frequency Dependent ◽  
Velocity Changes ◽  
Transient Pipe Flow ◽  
Laminar Pipe Flow ◽  
Experimental Pressure ◽  
Theoretical Results

An equation is derived, which relates the wall shear stress in transient laminar pipe flow to the instantaneous mean velocity and to the weighted past velocity changes. The term is applied to the method of characteristics to calculate water-hammer phenomena in viscous fluids, in which effects of frequency-dependent friction cause distortion of traveling waves. Theoretical results are compared with the experimental pressure fluctuation due to an instantaneous valve closure and show accurate prediction of the response curve.

scholarly journals Efficient iterative methods for finding simultaneously all the multiple roots of polynomial equation

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Mudassir Shams ◽  
Naila Rafiq ◽  
Nasreen Kausar ◽  
Praveen Agarwal ◽  
Choonkil Park ◽  
...  
Keyword(s):  
Iterative Methods ◽  
Computational Efficiency ◽  
Numerical Test ◽  
Polynomial Equation ◽  
Multiple Roots ◽  
Simultaneous Methods ◽  
Numerical Performance ◽  
Very High ◽  
High Computational Efficiency

AbstractTwo new iterative methods for the simultaneous determination of all multiple as well as distinct roots of nonlinear polynomial equation are established, using two suitable corrections to achieve a very high computational efficiency as compared to the existing methods in the literature. Convergence analysis shows that the orders of convergence of the newly constructed simultaneous methods are 10 and 12. At the end, numerical test examples are given to check the efficiency and numerical performance of these simultaneous methods.

scholarly journals Stellar magnetic imaging from spectropolarimetric data

1996 ◽  
Vol 176 ◽  
pp. 53-60 ◽  
Author(s):  
J.-F. Donati
Keyword(s):  
Small Amplitude ◽  
High Accuracy ◽  
Spectral Lines ◽  
New Method ◽  
Doppler Imaging ◽  
Magnetic Imaging ◽  
Active Stars ◽  
Surface Fields ◽  
Very High

In this paper, I will review the capabilities of magnetic imaging (also called Zeeman-Doppler imaging) to reconstruct spot distributions of surface fields from sets of rotationnally modulated Zeeman signatures in circularly polarised spectral lines. I will then outline a new method to measure small amplitude magnetic signals (typically 0.1% for cool active stars) with very high accuracy. Finally, I will present and comment new magnetic images reconstructed from data collected in 1993 December at the Anglo-Australian Telescope (AAT).

Hole Accuracy during Deep Hole Drilling for Hydraulic Cylinder Application

2014 ◽  
Vol 984-985 ◽  
pp. 67-72 ◽  
Author(s):  
R. Clifford Benjamin Raj ◽  
B. Anand Ronald ◽  
A. Velayudham ◽  
Prasmit Kumar Nayak
Keyword(s):  
Feed Rate ◽  
Drill Hole ◽  
Hydraulic Cylinder ◽  
High Accuracy ◽  
Diameter Ratio ◽  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Very High ◽  
Continuous Chip

Deep-hole drilling is a process in which the hole length will be very high when compared to diameter of the drill hole (i.e. length to diameter ratio will be greater than 5). Drilling a deep hole with very high accuracy is difficult process. The current project is about the production of deep hole with the aim to produce a chip which is not a continuous chip and also not a powdery chip. These conditions can be attained by varying the spindle speed and the tool feed rate.

The Sensitivity Simulation of Different Geometric Pretreatment in Method of Characteristics

2017 ◽  
Author(s):  
Tian XiaoRui ◽  
Zhou Tao ◽  
Li Zichao ◽  
Yu Tao
Keyword(s):  
Computational Efficiency ◽  
Method Of Characteristics ◽  
Azimuthal Angle ◽  
Reactor Core ◽  
Characteristic Line ◽  
Simulation Results ◽  
And Storage

In reactor core physics analysis,the research about the pre-processing of Method of Characteristic (MOC) including the generation and storage of characteristic line,the progress of calculation and the choosing of different quadrature set.In addition,doing some simulations,which is based on OpenMOC code and C5G7-MOX benchmark,about different parameters (including the track spacing,azimuthal angles and polar angles) and calculated its impacts on the computational efficiency and accuracy.the simulation results are as following:setting the track spacing as 0.1 cm or the azimuthal angle number as 4,the simulation results have better accuracy. Whether choosing the Leonard’s optimum quadrature set or the Tabuchi-Yamamoto quadrature set,the number of polar angles have tiny impact on accuracy.

Cost Effective Swath Bathymetry

2001 ◽  
Vol 35 (4) ◽  
pp. 33-45 ◽  
Author(s):  
Peter Hogarth
Keyword(s):  
Processing Time ◽  
Cost Effective ◽  
High Accuracy ◽  
High Coverage ◽  
Swath Bathymetry ◽  
World Survey ◽  
Set Up ◽  
Very High ◽  
Harbor Area ◽  
Wide Swath

Between 23rd and 25th July 2001 GeoSwath, a high specification shallow water wide swath bathymetry system, was used to survey the entire Portsmouth NH Harbor area. This paper deals with the results of this survey, illustrating the potential for significant reductions in the high costs, which have prevented widespread proliferation of Swath Bathymetry systems to date. Data, including a complete DTM gridded to 1 m resolution, will be presented and discussed in detail. These results show that the system is very easy to set up and use, requires greatly reduced boat and processing time, whilst offering high accuracy and very high coverage and resolution when used in a real-world survey of a dynamic harbor environment.

A New Method for Aggregate Proportion Design of Mixture

2012 ◽  
Vol 178-181 ◽  
pp. 1250-1253
Author(s):  
Yu Hua Li ◽  
Kai Huang ◽  
Ying Zhen Gao
Keyword(s):  
Iterative Algorithm ◽  
Accurate Result ◽  
High Accuracy ◽  
New Method ◽  
Equation Method ◽  
Normal Equation ◽  
Improved Method ◽  
Mixture Ratio ◽  
Target Value ◽  
Initial Target

When we make design of mixture ratio, we always use normal equation method (NEM), but the solution value of that method may doesn’t meet our demand. When we use the new method that proposed in this paper, we can solve the problem. The new method makes an improvement for NEM. By iterative algorithm, the new method uses the gradation data calculated by NEM as initial target value, canceling the relevant aggregate if the result of proportion is negative, and setting the gradation to the boundary value if the target value goes beyond limits. According to the adjusted object value, using NEM again, the new aggregate proportion can be solved. Then the new gradation of mixture will come into being the next target value. Finally, the accurate result will meet our need. The new improved method has good engineering applicability and high accuracy

M1212 Celiac Disease Serology with Very High Accuracy May Obviate Diagnostic Intestinal Biopsy in Different Clinical Scenarios

2008 ◽  
Vol 134 (4) ◽  
pp. A-362
Author(s):  
Emilia Sugai ◽  
María Laura Moreno ◽  
Hui Jer Hwang ◽  
Adriana Crivelli ◽  
Fabio Nachman ◽  
...  
Keyword(s):  
Celiac Disease ◽  
High Accuracy ◽  
Intestinal Biopsy ◽  
Clinical Scenarios ◽  
Very High
Sign in / Sign up

Export Citation Format

Share Document