scholarly journals Parameter Identification of the 2-Chlorophenol Oxidation Model Using Improved Differential Search Algorithm

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Guang-zhou Chen ◽  
Jia-quan Wang ◽  
Ru-zhong Li
Keyword(s):  
Sensitivity Analysis ◽  
Parameter Identification ◽  
Sampling Method ◽  
Hybrid Methods ◽  
Latin Hypercube Sampling ◽  
The Other ◽  
Posteriori Probability ◽  
Initial Population ◽  
Latin Hypercube ◽  
Oxidation Model

Parameter identification plays a crucial role for simulating and using model. This paper firstly carried out the sensitivity analysis of the 2-chlorophenol oxidation model in supercritical water using the Monte Carlo method. Then, to address the nonlinearity of the model, two improved differential search (DS) algorithms were proposed to carry out the parameter identification of the model. One strategy is to adopt the Latin hypercube sampling method to replace the uniform distribution of initial population; the other is to combine DS with simplex method. The results of sensitivity analysis reveal the sensitivity and the degree of difficulty identified for every model parameter. Furthermore, the posteriori probability distribution of parameters and the collaborative relationship between any two parameters can be obtained. To verify the effectiveness of the improved algorithms, the optimization performance of improved DS in kinetic parameter estimation is studied and compared with that of the basic DS algorithm, differential evolution, artificial bee colony optimization, and quantum-behaved particle swarm optimization. And the experimental results demonstrate that the DS with the Latin hypercube sampling method does not present better performance, while the hybrid methods have the advantages of strong global search ability and local search ability and are more effective than the other algorithms.

Uncertainty Quantification of Turbulence Model Coefficients via Latin Hypercube Sampling Method

2010 ◽  
Author(s):  
Matthew C. Dunn ◽  
Babak Shotorban ◽  
Abdelkader Frendi
Keyword(s):  
Uncertainty Quantification ◽  
Turbulent Flows ◽  
Turbulence Model ◽  
Sampling Method ◽  
Latin Hypercube Sampling ◽  
Recirculation Region ◽  
Free Shear Layer ◽  
Latin Hypercube ◽  
Reattachment Point ◽  
Turbulent Dissipation

This paper is concerned with the propagation of uncertainties in the values of turbulence model coefficients and parameters in turbulent flows. These coefficients and parameters are determined from experiments performed on elementary flows and they are subject to uncertainty. The widely used k–ε turbulence model is considered. It consists of model transport equations for the turbulence kinetic energy and rate of turbulent dissipation. Both equations involve various model coefficients about which adequate knowledge is assumed known in the form of probability density functions. The study is carried out for the flow over a 2D backward-facing step configuration. The Latin Hypercube Sampling method is employed for the uncertainty quantification purposes as it requires a smaller number of samples compared to the conventional Monte-Carlo method. The mean values are reported for the flow output parameters of interest along with their associated uncertainties. The results show that model coefficient variability has significant effects on the streamwise velocity component in the recirculation region near the reattachment point and turbulence intensity along the free shear layer. The reattachment point location, pressure, and wall shear are also significantly affected.

Development of Statistical Core Thermal Design Methodology Using a Modified Latin Hypercube Sampling Method

1991 ◽  
Vol 94 (3) ◽  
pp. 407-415 ◽  
Author(s):  
Seung-Hyuk Lee ◽  
Hyun-Koon Kim ◽  
Sang-Ryeol Park ◽  
Soon-Heung Chang
Keyword(s):  
Design Methodology ◽  
Sampling Method ◽  
Latin Hypercube Sampling ◽  
Thermal Design ◽  
Latin Hypercube

A Probabilistic Safety Assessment Method Based on Latin Hypercube Sampling Method

2015 ◽  
Vol 757 ◽  
pp. 159-163
Author(s):  
Ying Juan Yue ◽  
Fei Chen ◽  
Hong Li ◽  
Hai Xia Du ◽  
Xiao Jun Du
Keyword(s):  
Change Process ◽  
Safety Assessment ◽  
Sampling Method ◽  
Latin Hypercube Sampling ◽  
Assessment Method ◽  
Probabilistic Assessment ◽  
Latin Hypercube ◽  
Probabilistic Safety Assessment ◽  
Failure Assessment ◽  
Probabilistic Safety

Based on the shortcomings of traditional probabilistic assessment methods, an improved probabilistic safety assessment method was proposed, which used Latin hypercube sampling, considered the change process about fatigue crack propagation, as well as the effect of random variables on the failure assessment curve. The paper also analyzed the specific example with this method. The results showed that this method was simpler and more effective, which had some value of applications in engineering.

Research on the Micro-Mechanical State at Tip of Environmentally Assisted Cracking Based on Latin Hypercube Sampling Method

2019 ◽  
Vol 795 ◽  
pp. 74-78
Author(s):  
Kuan Zhao ◽  
He Xue ◽  
Ling Yan Zhao
Keyword(s):  
Oxide Film ◽  
Material Properties ◽  
Nuclear Power ◽  
Power Plants ◽  
Sampling Method ◽  
Latin Hypercube Sampling ◽  
Primary Circuit ◽  
Mechanical State ◽  
Latin Hypercube ◽  
Environmentally Assisted Cracking

Environmentally assisted cracking (EAC) of nickel-based alloys is one of the most significant potential safety hazards in the primary circuit of nuclear power plants. To understand the influence of randomness on micro-mechanical state at tip of EAC, Latin hypercube sampling method is applied to analyze the uncertainty of stress-strain in the oxide film at the EAC tip considering the uncertainties of load and material properties of base metal and oxide film. Meanwhile, to improve the efficiency of numerical analysis, MATLAB is employed in the secondary development for ABAQUS. With the help of finite element numerical simulation and Latin hypercube sampling method, the uncertainty of mechanical properties at tip of EAC in one-inch compact tension specimen is simulated and analyzed in this study. The results show that the randomness of material properties and load markedly affect the uncertainty of micro-mechanical state. Among the variables, The randomness of load has the greatest influence on uncertainty of strain, and Poisson`s ratio of oxide film is the smallest effect.

Uncertainty Quantification of Turbulence Model Coefficients via Latin Hypercube Sampling Method

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Matthew C. Dunn ◽  
Babak Shotorban ◽  
Abdelkader Frendi
Keyword(s):  
Uncertainty Quantification ◽  
Turbulent Flows ◽  
Turbulence Model ◽  
Sampling Method ◽  
Latin Hypercube Sampling ◽  
Recirculation Region ◽  
Free Shear Layer ◽  
Latin Hypercube ◽  
Reattachment Point ◽  
Mean Velocity

The article is concerned with the propagation of uncertainties in the values of turbulence model coefficients and parameters in turbulent flows. These coefficients and parameters are obtained through experiments performed on elementary flows, and they are subject to uncertainty. In this work, the widely used k-ɛ turbulence model is considered. It consists of model transport equations for the turbulence kinetic energy and the rate of turbulent dissipation. Both equations involve various model coefficients about which adequate knowledge is assumed known in the form of probability density functions. The study is carried out for a flow over a 2D backward-facing step configuration. The Latin Hypercube Sampling method is employed for the uncertainty quantification purposes as it requires a smaller number of samples compared to the conventional Monte Carlo method. The mean values are reported for the flow output parameters of interest along with their associated uncertainties. The results show that model coefficient variability has significant effects on the streamwise mean velocity in the recirculation region near the reattachment point and turbulence intensity along the free shear layer. The reattachment point location, pressure, and wall shear are also significantly influenced by the uncertainties of the coefficients.

Sensitivity Analysis of Stress State of Welded Tanks

2015 ◽  
Vol 769 ◽  
pp. 3-8
Author(s):  
Zdenek Kala ◽  
Jakub Gottvald ◽  
Jakub Stonis ◽  
Stanislav Vejvoda ◽  
Abayomi Omishore
Keyword(s):  
Sensitivity Analysis ◽  
Stress State ◽  
Hydrostatic Pressure ◽  
Crude Oil ◽  
Computational Model ◽  
Sampling Method ◽  
Latin Hypercube Sampling ◽  
Load Case ◽  
Cylindrical Tank ◽  
Stochastic Sensitivity Analysis

This article focuses on the reliability analysis of a welded cylindrical tank, which is used for the storage of crude oil. The dominant load case is loading of the inner shell by hydrostatic pressure of the crude oil. Stochastic sensitivity analysis was used to study the effect of the variability of the thickness of the ith course on the stress state of adjacent courses. The computational model was developed in the programme ANSYS. Meshing was performed using SHELL181 elements. The Latin Hypercube Sampling method was implemented during analysis. Sensitivity analysis based on the evaluation of the correlation between the random plate thicknesses and the stress state was performed.

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