Deterministic Reproduction of Nonlinear Waves

2002 ◽  
Author(s):  
Jesper Skourup ◽  
Martin J. Sterndorff
Keyword(s):  
Time Series ◽  
Nonlinear Waves ◽  
Second Order ◽  
Irregular Waves ◽  
Regular Waves ◽  
Order Model ◽  
Wave Flume ◽  
Non Linear ◽  
The Waves ◽  
Second Order Model

A method for deterministic reproduction of non-linear long-crested waves has been implemented. The model is used for non-linear reproduction of measured wave time series from a model test programme in a wave flume. Regular waves, irregular waves and focused waves have been reproduced with the model. Based on measured surface elevation time series at one location in the flume the elevation time series and the kinematics have been reproduced at another location using both linear theory and the second order model. The numerical results have been compared with measurements and it is found that the second order model is able to reproduce the correct shape of the waves as they propagate in the flume — even when the waves are highly non-linear.

Second-Order Kinematics Underneath Irregular Waves

2013 ◽  
Author(s):  
Jørn Birknes ◽  
Øistein Hagen ◽  
Thomas B. Johannessen ◽  
Øystein Lande ◽  
Arne Nestegård
Keyword(s):  
Free Surface ◽  
Water Level ◽  
Model Test ◽  
Second Order ◽  
Horizontal Velocity ◽  
Irregular Waves ◽  
Test Results ◽  
Order Model ◽  
Main Challenge ◽  
Second Order Model

The present paper is concerned with the prediction of horizontal velocities underneath measured irregular wave surface elevations. The simple case of unidirectional waves in deep water is considered. The main challenge in calculating accurately the kinematics in the crest region is related to the treatment of the contribution from wave components with frequencies much higher than the frequencies near the spectral peak. When using linear or weakly nonlinear perturbation methods, the wave components are superimposed at the still water level and it is necessary to truncate the tail of the spectrum in order to calculate accurately the velocity in the crest region. In the present paper, results from three methods of calculating the crest kinematics are compared with the model test results of Skjelbreia et al. [1]: • The second-order model of Stansberg et al. [5] which truncates consistently the high frequency part of the spectrum. • The second-order model of Johannessen [13] which calculates the velocity directly at the instantaneous free surface. • The Wheeler [3] stretching method which stretches the linear velocity profile from the still water level to the instantaneous free surface. In addition to comparing the horizontal velocity profiles underneath the crest, time traces of horizontal velocity is compared at the free surface in the vicinity of a large crest. The latter comparison highlights the differences between the models and the challenge of accurate predictions close to top of crest. All three models show a reasonable agreement with model test results although it is clear that the first two methods are superior to the Wheeler method.

scholarly journals Comparison of Non-Linear and Linear Ho Models Applied for Copper Ions Sorption on Geopolymer

2021 ◽  
Vol 15 (3) ◽  
pp. 305-309
Author(s):  
Mario Nikola Mužek ◽  
Sandra Svilović ◽  
Jelica Zelić
Keyword(s):  
Copper Ions ◽  
Sorption Process ◽  
Second Order ◽  
Order Model ◽  
Experimental Conditions ◽  
Non Linear ◽  
Best Fitting ◽  
Pseudo Second Order ◽  
Made In ◽  
Second Order Model

The Ho pseudo-second-order model is the best fitting model in describing the sorption of copper ions on synthesized geopolymer for the selected experimental conditions (particle size 0.071–0.090 mm at agitation speed of 240 rpm). For that reason, a comparison of one non-linear and five linear forms of the Ho pseudo-second-order model was made in the present study in order to obtain the optimum sorption kinetic parameters using the experimental kinetic data obtained for the copper ions sorption process on the synthesized geopolymer. Taking all the results into consideration, the non-linear Ho model proved to be more consistent in describing the copper ions sorption on geopolymer for various initial concentrations of sorbent, as well as for various temperatures.

Adsorption Kinetics of Pb2+ Ions Using Chitosan Nanoparticles

2013 ◽  
Vol 367 ◽  
pp. 45-49
Author(s):  
Ying Hong ◽  
Ze Hui Zhong ◽  
You Shi Liu
Keyword(s):  
Adsorption Kinetics ◽  
Chitosan Nanoparticles ◽  
Second Order ◽  
Isotherm Model ◽  
Order Model ◽  
Adsorption Characteristics ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Second Order Model

Chitosan nanoparticles were prepared by crosslinkingusing TPP. SEM showed that chitosan nanoparticles were successfully obtained.The adsorption characteristics of chitosan nanoparticles were evaluated. Theresults demonstrated that chitosan nanoparticles were suitable for adsorbent toremoval Pb2+. The parameters for the adsorption of Pb2+by chitosan nanoparticles were also determined. It was shown that chitosannanoparticles were fit for Langmuir’s isotherm model and that the adsorptionkinetics of Pb2+ described by the pseudo-second-order model could bebest.

Polyaniline/ZnO nanocomposites for the removal of methyl orange dye from waste water

2018 ◽  
Vol 32 (19) ◽  
pp. 1840085 ◽  
Author(s):  
Neha V. Nerkar ◽  
Subhash B. Kondawar ◽  
Snehal Kargirwar Brahme ◽  
Yun Hae Kim
Keyword(s):  
Waste Water ◽  
Methyl Orange ◽  
Adsorption Mechanism ◽  
Second Order ◽  
Pure Pani ◽  
Time Interval ◽  
Order Model ◽  
Vis Spectroscopy ◽  
Pseudo Second Order ◽  
Second Order Model

In this paper, we report the safe removal of methyl orange (MO) dye from aqueous solution using chemical interaction of dye molecule with polyaniline/zinc oxide (PANI/ZnO) nanocomposite. PANI/ZnO nanocomposite has been prepared by in situ polymerization. PANI/ZnO nanocomposite was found to be the best promising candidate for adsorption of dyes due to more porosities compared to that of pure PANI. In the present investigation, PANI/ZnO nanocomposite was mixed in a solution of MO dye and used for adsorption process. Color removal was studied using UV-Vis spectroscopy and the spectra were recorded for specific time interval and validation of kinetic model has been applied. Absorbance of PANI/ZnO nanocomposite was found to be increased as compared to that of pure ZnO nanoparticles and pure PANI due to synergistic effect. Comparatively, the removal of dye was also found to be more by using PANI/ZnO nanocomposites. In order to evaluate kinetic mechanism the pseudo-first-order model, pseudo-second-order model and intraparticle diffusion models were verified by the linear equation analysis. Adsorption mechanism of pseudo-second-order model was systematically explained for removal of dye using PANI/ZnO nanocomposite. The results clearly demonstrated that the adsorption mechanism gives very novel and green method of removal of hazardous dyes from waste water.

scholarly journals Validating a second-order model for oil and gas projects’ investment climate scale

2017 ◽  
Vol 11 (1) ◽  
pp. 65-79 ◽  
Author(s):  
Abdulsalam Mas’ud ◽  
Nor Aziah Abd Manaf ◽  
Natrah Saad
Keyword(s):  
Goodness Of Fit ◽  
Oil And Gas ◽  
Second Order ◽  
Fit Indices ◽  
Investment Climate ◽  
Order Model ◽  
Content Type ◽  
Latent Construct ◽  
Climate Scale ◽  
Second Order Model

Purpose The investment climate is one of the key factors considered by foreign investors while deciding their investment destination. This paper aims to attempt at validating the second-order model of oil and gas projects’ investment climate. Examination of the relationship between the dimensions of oil and gas projects’ investment climate; strategy, participants/operating environment and risk/return; and the overall latent construct was conducted. The study also evaluates the goodness of fit of the second-order model using relevant fit indices. Design/methodology/approach Oil and gas experts in Malaysian marginal oil fields subsector were deployed, through whom responses were collected that formed the data set used in the analysis. Then, the data were used for confirmatory factor analysis, evaluation of the second-order model through path analysis and for model fit evaluation. Findings The finding revealed that the second-order model of oil and gas projects’ investment climate is valid and reliable. It also revealed that all the three dimensions, strategy, participants/operating environment and risk/return, have significant effects on the formation of the oil and gas projects’ investment climate. Finally, the goodness of fit of the second-order model satisfied the relevant fit indices. Research limitations/implications The findings present valuable insights to policymakers on the extent of the influence each of the dimensions has on the overall latent construct. The validity and reliability analysis suggests the measurements of the second-order model of oil and gas projects’ investment climate construct, and its dimensions are valid, reliable and fit for future empirical research. Thus, it calls for replication in other oil and gas settings. Originality/value The findings from the results of this study are pioneering. Extant literature falls short in attempting the validation of the second-order oil and gas projects’ investment climate scale, as well as relating each of the dimensions with the overall latent construct.

Sign in / Sign up

Export Citation Format

Share Document