An Efficient Method for Simulating Frequency-Dependent Friction in Transient Liquid Flow

1975 ◽  
Vol 97 (1) ◽  
pp. 97-105 ◽  
Author(s):  
A. K. Trikha
Keyword(s):  
Liquid Flow ◽  
Method Of Characteristics ◽  
Computation Time ◽  
Approximate Expression ◽  
Test System ◽  
Exact Expression ◽  
Frequency Dependent ◽  
Efficient Procedure ◽  
Liquid Line ◽  
Frequency Domains

An efficient procedure is developed for simulating frequency-dependent friction in transient laminar liquid flow by the method of characteristics. The procedure consists of determining an approximate expression for frequency-dependent friction such that the use of this expression requires much less computer storage or computation time than the use of the exact expression. The derived expression for frequency-dependent friction approximates the exact expression very well in both time and frequency domains. Calculated results for a test system are compared with the experimental results so show that the approximate expression predicts accurately the surge pressures, pressure wave distortion as well as pressure attenuation in a liquid line.

Improving Zielke’s Method of Simulating Frequency-Dependent Friction in Laminar Liquid Pipe Flow

1991 ◽  
Vol 113 (4) ◽  
pp. 569-573 ◽  
Author(s):  
Katsumasa Suzuki ◽  
Takayuki Taketomi ◽  
Sanroku Sato
Keyword(s):  
Method Of Characteristics ◽  
Weighting Function ◽  
Block Diagram ◽  
Computation Time ◽  
Dimensionless Time ◽  
Frequency Dependent ◽  
Transient Phenomena ◽  
Computer Storage ◽  
Calculation Process ◽  
Visual Understanding

Zielke’s technique of using a method of characteristics to simulate transient phenomena of a liquid transmission line is accurate, easy to apply to complicated systems and therefore, frequently used. However, it requires a very large amount of computation time and computer storage to simulate frequency-dependent friction in a transient liquid flow. Searching for a way to counteract these disadvantages, the authors took note of the fact that the weighting function, which is the root of the above problems, is given by exponential functions or other functions depending on dimensionless time. In order to perform mathematically equivalent calculation without approximations, they have developed a new method which requires much less computation time and computer storage than Zielke’s method. The calculation process is shown by a block diagram to facilitate visual understanding of the method.

Thermoelastic Damping in Axially Stressed Beam

2008 ◽  
Author(s):  
Sandeep Kumar ◽  
Amanul Haque
Keyword(s):  
Axial Stress ◽  
Approximate Expression ◽  
Exact Expression ◽  
Q Factor ◽  
Thermoelastic Damping ◽  
General Behavior ◽  
Limiting Case

Zener’s approximate expression for thermoelastic damping was first known attempt to quantify the thermoelastic damping. Recently, an exact expression of thermoelastic damping for thin unstressed beams, which is widely used, is arrived at. Further, it has been experimentally verified that application of tensile axial stress results in increase in the Q-factor. Since the existing expressions do not take into account the effect of axial stress thermoelastic-damping expression is revised in order to accommodate the effect of axial stress on Q-factor. This expression explains the general behavior observed in experiments. In limiting case of unstressed beam, this new expression converges to current expression for thermoelastic damping.

scholarly journals A Parallel Implementation of Unscheduled Flow Control in Interconnected Power Systems

2012 ◽  
Vol 2012 ◽  
pp. 1-19
Author(s):  
G. Ozdemir Dag ◽  
Mustafa Bagriyanik
Keyword(s):  
Power Systems ◽  
Power System ◽  
Parallel Computation ◽  
High Performance ◽  
Power Flow ◽  
Parallel Implementation ◽  
Computation Time ◽  
Test System ◽  
Fuzzy Decision Making ◽  
Optimization Approach

The unscheduled power flow problem needs to be minimized or controlled as soon as possible in a deregulated power system since the transmission systems are mostly operated at their power-carrying limits or very close to it. The time spent for simulations to determine the current states of all the system and control variables of the interconnected power system is important. Taking necessary action in case of any failure of equipment or any other occurrence of an undesired situation could be critical. Using supercomputing facilities and parallel computing techniques together decreases the computation time greatly. In this study, a parallel implementation of a multiobjective optimization approach based on both genetic algorithms and fuzzy decision making to manage unscheduled flows is presented. Parallel computation techniques are applied using supercomputers (high-performance computers). The proposed method is applied to the IEEE 300 bus test system. Two different cases for some parameters of GA are considered to see the power of parallel computation technique. Then the simulation results are presented.

Prediction of Undervoltage Load Shedding Using Quantum-Inspired Evolutionary Programming-Support Vector Machine

2015 ◽  
Vol 785 ◽  
pp. 43-47
Author(s):  
Zuhaila Mat Yasin ◽  
Zuhaina Zakaria ◽  
Titik Khawa Abdul Rahman
Keyword(s):  
Support Vector Machine ◽  
Computation Time ◽  
Evolutionary Programming ◽  
Test System ◽  
Least Square ◽  
Support Vector ◽  
Rbf Kernel ◽  
Validation Procedure ◽  
Programming Support ◽  
A New Technique

This paper presents a new technique to predict the optimal amount of load to be shed at various loading conditions using Quantum-Inspired Evolutionary Programming–Support Vector Machine (QIEP-SVM). QIEP is utilised to optimise the RBF Kernel parameters in Least-Square Support Vector Machine (LS-SVM). The objective of the optimisation is to minimise the mean square error (MSE). The performance of QIEP-SVM technique was compared with those obtained from LS-SVM technique with prediction accuracy through a 10-fold cross-validation procedure. All simulations in this study were carried out using IEEE 69-bus distribution test system. QIEP-SVM model had shown better prediction performance as compared to LS-SVM. The results also indicate that the proposed approach outperforms the most recently reported technique in terms of accuracy and fast computation time.

Numerical evaluation of the transient acoustic waveform due to a point source in a fluid‐filled borehole

Geophysics ◽  
1979 ◽  
Vol 44 (10) ◽  
pp. 1706-1720 ◽  
Author(s):  
Leung Tsang ◽  
Dennis Rader
Keyword(s):  
Numerical Methods ◽  
Point Source ◽  
Numerical Evaluation ◽  
Close Agreement ◽  
Time Windows ◽  
Computation Time ◽  
Head Wave ◽  
Oil Well ◽  
Additional Information ◽  
Frequency Domains

A key measurement employed in oil well wireline logging is the acoustic wave traveltime over a specified formation interval, typically 1 ft. In the traditional measurement, only the compressional head wave is monitored, but for some time it has been obvious that there is significant additional information, such as the shear head wave arrival, in the received waveform. We describe two numerical methods for computing the profile and parameter dependence of the transient waveform based on a model of the acoustic logging problem consisting of a point source on the axis of a fluid‐filled cylindrical borehole. The response to this excitation is determined at a distance from the source, generally on the borehole axis. In the first of the two numerical methods, called “real axis integration”, the complete acoustic waveform is obtained. The second method, called “branch‐cut integration”, evaluates the first compressional and shear‐pseudo‐Rayleigh arrivals individually with much less computation time than the first method. The validity and accuracy of the two methods are demonstrated by their close agreement within appropriate time windows. It is also shown that the results from the ordinary asymptotic method that exist in the literature predict different behavior. The dependence of the transient arrivals on formation parameters is illustrated by various numerical results in both time and frequency domains.

scholarly journals Metaheuristic searching genetic algorithm based reliability assessment of hybrid power generation system

2020 ◽  
pp. 014459872095974
Author(s):  
Ahmed N Abdalla ◽  
Muhammad Shahzad Nazir ◽  
MingXin Jiang ◽  
Athraa Ali Kadhem ◽  
Noor Izzri Abdul Wahab ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Power Generation ◽  
Solar Energy ◽  
Computation Time ◽  
Test System ◽  
Optimization Approach ◽  
Generation System ◽  
Power Sources ◽  
Hybrid Power ◽  
Power Generation System

Generating systems are known as adequately reliable when satisfying the load demand. Meanwhile, the efficiency of electrical systems is currently being more influenced by the growing adoption of the Wind/Solar energy in power systems compared to other conventional power sources. This paper proposed a new optimization approach called Metaheuristic Scanning Genetic Algorithm (MSGA) for the evaluation of the efficiency of power generating systems. The MSGA is based on a combination of metaheuristic scanning and Genetic Algorithm. The MSGA technique is used for evaluating the reliability and adequacy of generation systems integrated with wind/Solar energy is developed. The usefulness of the proposed algorithm was tested using Reliability Test System ‘IEEE-RTS-79’ which include both of wind power and solar power generation. The result approve the effectiveness of the proposed algorithm in improving the computation time by 85% and 2% in comparison with the particle swarm optimization (PSO) and differential evolution optimization algorithm (DEOA) respectively. In addition, the proposed model can be used to test the power capacity forecasting scheme of the hybrid power generation system with the wind, solar and storage.

A Dynamic Evaluation Technique for Liquid Flow Meters Based on Hydraulic Line Dynamics

1997 ◽  
Vol 119 (2) ◽  
pp. 305-307
Author(s):  
Guangzheng Peng ◽  
Tong Zhao
Keyword(s):  
Dynamic Characteristics ◽  
Liquid Flow ◽  
Experimental Verification ◽  
Microcomputer System ◽  
Evaluation Technique ◽  
Flow Meters ◽  
Pressure Transducers ◽  
Dynamic Technique ◽  
Frequency Domains ◽  
Flow Generator

A new concept for the evaluation of flowmeter dynamic response is presented. A technique based on hydraulic line dynamics is applied to achieve accurate measurements of the reference flowrate. The major components in the equipment used in experimental verification of the theory were a test pipe, a pulsating flow generator, three pressure transducers, an A/D converter, and a microcomputer system. This equipment allowed the dynamic characteristics of a flowmeter to be investigated in both the time and frequency domains. Comparisons of flowrates measured using the line dynamic technique and the same flowrates recorded by the flowmeter are presented. The results confirm the feasibility and practicability of the dynamic line technique for measuring rapidly varying flows.

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