Overview of the experimental studies and numerical simulations on the filtered containment venting systems with wet scrubbers

2019 ◽  
Vol 132 ◽  
pp. 461-485 ◽  
Author(s):  
Shichang Dong ◽  
Jun Yang
Keyword(s):  
Numerical Simulations ◽  
Experimental Studies ◽  
Wet Scrubbers

Vortex-Induced Vibrations of a Cylinder at Subcritical Reynolds Number

2011 ◽  
Author(s):  
Yoann Jus ◽  
Elisabeth Longatte ◽  
Jean-Camille Chassaing ◽  
Pierre Sagaut
Keyword(s):  
Reynolds Number ◽  
Numerical Simulations ◽  
Numerical Study ◽  
Damping Ratio ◽  
Experimental Studies ◽  
Cross Flow ◽  
Physical Analysis ◽  
Arbitrary Lagrangian Eulerian ◽  
Vortex Induced Vibrations ◽  
Low Mass

The present work focusses on the numerical study of Vortex-Induced Vibrations (VIV) of an elastically mounted cylinder in a cross flow at moderate Reynolds numbers. Low mass-damping experimental studies show that the dynamic behavior of the cylinder exhibits a three-branch response model, depending on the range of the reduced velocity. However, few numerical simulations deal with accurate computations of the VIV amplitudes at the lock-in upper branch of the bifurcation diagram. In this work, the dynamic response of the cylinder is investigated by means of three-dimensional Large Eddy Simulation (LES). An Arbitrary Lagrangian Eulerian framework is employed to account for fluid solid interface boundary motion and grid deformation. Numerous numerical simulations are performed at a Reynolds number of 3900 for both no damping and low-mass damping ratio and various reduced velocities. A detailed physical analysis is conducted to show how the present methodology is able to capture the different VIV responses.

Crashworthiness Performance of Mass-Efficient Extruded Structures

2002 ◽  
Author(s):  
Robert R. Mayer ◽  
Weigang Chen ◽  
Anil Sachdev
Keyword(s):  
Numerical Simulations ◽  
Single Cell ◽  
Experimental Testing ◽  
Experimental Studies ◽  
Nonlinear Material ◽  
Dynamic Strain ◽  
Cell Design ◽  
Explicit Finite Element ◽  
The One ◽  
Crushing Behavior

Theoretical, numerical and experimental studies were conducted on the axial crushing behavior of traditional single-cell and innovative four-cell extrusions. Two commercial aluminum alloys, 6061 and 6063, both with two tempers (T4 and T6), were considered in the study. Testing coupons taken from the extrusions assessed the nonlinear material properties. A theoretical solution was available for the one-cell design, and was developed for the mean crushing force of the four-cell section. Numerical simulations were carried out using the explicit finite element code LS-DYNA. The aluminum alloy 6063T4 was found to absorb less energy than 6061T4, for both the one-cell and four-cell configurations. Both 6061 and 6063 in the T6 temper were found to have significant fracture in the experimental testing. Theoretical analysis and numerical simulations predicted a greater number of folds for the four-cell design, as compared to the one-cell design, and this was confirmed in the experiments. The theoretical improvement in energy absorption of 57% for the four-cell in comparison with the one-cell design was confirmed by experiment. The good agreement between the theoretical, numerical and experimental results allows confidence in the application of the theoretical and numerical tools for both single-cell and innovative four-cell extrusions. It was also demonstrated that these materials have very little dynamic strain rate effect.

Hysteretic effects of dry friction: modelling and experimental studies

2007 ◽  
Vol 366 (1866) ◽  
pp. 747-765 ◽  
Author(s):  
Jerzy Wojewoda ◽  
Andrzej Stefański ◽  
Marian Wiercigroch ◽  
Tomasz Kapitaniak
Keyword(s):  
Numerical Simulations ◽  
Dry Friction ◽  
Experimental Studies ◽  
Friction Model ◽  
Hysteretic Effect ◽  
Motion Characteristic ◽  
Friction Models ◽  
Theoretical Analyses ◽  
Friction Modelling

In this paper, the phenomena of hysteretic behaviour of friction force observed during experiments are discussed. On the basis of experimental and theoretical analyses, we argue that such behaviour can be considered as a representation of the system dynamics. According to this approach, a classification of friction models, with respect to their sensitivity on the system motion characteristic, is introduced. General friction modelling of the phenomena accompanying dry friction and a simple yet effective approach to capture the hysteretic effect are proposed. Finally, the experimental results are compared with the numerical simulations for the proposed friction model.

scholarly journals Experiments and simulations on the possibility of radiative contraction/collapse in the PF-1000 plasma focus

Nukleonika ◽  
2016 ◽  
Vol 61 (2) ◽  
pp. 145-148 ◽  
Author(s):  
Mohamad Akel ◽  
Jakub Cikhardt ◽  
Pavel Kubes ◽  
Hans-Joachim Kunze ◽  
Sing Lee ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Plasma Focus ◽  
Experimental Studies ◽  
Radiative Losses

Abstract Experimental studies of discharges in the plasma focus facility with neon filling and respective numerical simulations employing the radiative Lee code are reported. The pinch currents exceed the Pease-Braginskii current, which indicates that radiative losses are larger than heating and that contraction of the formed plasma should occur. Both of these effects were indeed observed. Parallel numerical simulations were crucial for the identification of such an effect.

Numerical simulations of preliminary state of stress in bundles of metal sheets on the guillotine

2017 ◽  
Vol 85 (1) ◽  
pp. 14-23 ◽  
Author(s):  
J. Kaczmarczyk
Keyword(s):  
Numerical Simulations ◽  
Experimental Studies ◽  
Cutting Parameters ◽  
Cutting Process ◽  
Main Task ◽  
Force Loading ◽  
State Of Stress ◽  
Metal Sheets ◽  
Optimum Cutting ◽  
Selection Of

Purpose: The work is aimed at determination of the influence of selected technological parameters on the preliminary state of stress in bundles of metal sheets being compressed by the pressure beam and submitted to the cutting process on a guillotine. Design/methodology/approach: The numerical simulations concerning the preliminary state of stress in the bundle of sheets were conducted by means of the finite element method and the computer system MSC.Patran with the computational module MSC.Marc. The experimental studies concerning the influence of a force loading the pressure beam on the quality of metal sheets were carried out using scanning electron microscopy. Findings: Possibilities of finding the optimum cutting parameters to maximise the values of preliminary state of stress in the bundle of metal sheets subjected to cutting. Higher values of stresses in the bundle coming from loading the pressure beam on the one hand decrease the maximum values of cutting force and thereby facilitate the performance of the cutting process, however on the other hand too high values of stresses might damage the surface of the top sheet in a bundle. Research limitations/implications: The main task of the presented research concerns the reduction of the maximum force generated on a knife during the cutting process. It is possible by increasing the values of preliminary state of stress realized in practice by applying higher values of a force loading the pressure beam. The force should not be too high in order to avoid damaging of the top sheet in the bundle loading by the pressure beam. Practical implications: The appropriate selection of the cutting parameters on account of preliminary state of stress in the bundle of sheets is essential in terms of industrial economy. It enables reducing the amount of waste caused by defects in bundles of sheets and decreases wear of the cutting tool. The research has been conducted in order to reduce the number of randomly occurring defects during cutting of metal sheets on a guillotine. Originality/value: The results acquired from the research facilitate selection of the best parameter settings required for conducting the optimum cutting process on a guillotine. The optimum set of cutting parameters leads to the reduction of defects’ number occurring during the process.

scholarly journals Wear Processes in a Mechanical Friction Clutch: Theoretical, Numerical, and Experimental Studies

2015 ◽  
Vol 2015 ◽  
pp. 1-28 ◽  
Author(s):  
Dariusz Grzelczyk ◽  
Jan Awrejcewicz
Keyword(s):  
Mathematical Modeling ◽  
Experimental Data ◽  
Numerical Analysis ◽  
Numerical Simulations ◽  
Experimental Studies ◽  
Friction Torque ◽  
Wear Properties ◽  
Wear Model ◽  
Differential Model ◽  
Friction Clutch

Mathematical modeling, theoretical/numerical analysis, and experimental verification of wear processes occurring on the contact surface of friction linings of a mechanical friction clutch are studied. In contrast to many earlier papers we take into consideration wear properties and flexibility of friction materials being in friction contact. During mathematical modeling and numerical simulations we consider a general nonlinear differential model of wear (differential wear model) and a model of wear in the integral form (integral wear model). Equations governing contact pressure and wear distributions of individual friction linings, decrease of distance between clutch shields, and friction torque transmitted by the clutch are derived and compared with experimental data. Both analytical and numerical analyses are carried out with the qualitative and quantitative theories of differential and integral equations, including the Laplace transform approach to ODEs. We show that theoretical results and numerical simulations agree with the experimental data. Finally, a numerical analysis of the proposed mathematical models was carried out in a wider range of parameters of the considered system.

Redox Processes in Early Earth Accretion and in Terrestrial Bodies

Elements ◽  
2020 ◽  
Vol 16 (3) ◽  
pp. 161-166 ◽  
Author(s):  
Kevin Righter ◽  
Christopher D. K. Herd ◽  
Asmaa Boujibar
Keyword(s):  
Numerical Simulations ◽  
Liquid Water ◽  
Experimental Studies ◽  
Early Earth ◽  
Redox Processes ◽  
Natural Materials ◽  
The Earth

The Earth is a unique rocky planet with liquid water at the surface and an oxygen-rich atmosphere, consequences of its particular accretion history. The earliest accreting bodies were small and could be either differentiated and undifferentiated; later larger bodies had formed cores and mantles with distinct properties. In addition, there may have been an overall trend of early reduced and later oxidized material accreting to form the Earth. This paper provides an overview—based on natural materials in our Earthbound sample collections, experimental studies on those samples, and calculations and numerical simulations of differentiation processes—of planetary accretion, core–mantle equilibration, mantle redox processes, and redox variations in Earth, Mars, and other terrestrial bodies.

A Theoretical Model for the Regulation of Sex-lethal, a Gene That Controls Sex Determination and Dosage Compensation in Drosophila melanogaster

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1355-1384
Author(s):  
Matthieu Louis ◽  
Liisa Holm ◽  
Lucas Sánchez ◽  
Marcelle Kaufman
Keyword(s):  
Drosophila Melanogaster ◽  
Theoretical Model ◽  
Sex Determination ◽  
Numerical Simulations ◽  
Cell Fate ◽  
Regulatory Gene ◽  
Experimental Studies ◽  
Formal Basis ◽  
Sex Lethal ◽  
Specific Regulation

Abstract Cell fate commitment relies upon making a choice between different developmental pathways and subsequently remembering that choice. Experimental studies have thoroughly investigated this central theme in biology for sex determination. In the somatic cells of Drosophila melanogaster, Sex-lethal (Sxl) is the master regulatory gene that specifies sexual identity. We have developed a theoretical model for the initial sex-specific regulation of Sxl expression. The model is based on the well-documented molecular details of the system and uses a stochastic formulation of transcription. Numerical simulations allow quantitative assessment of the role of different regulatory mechanisms in achieving a robust switch. We establish on a formal basis that the autoregulatory loop involved in the alternative splicing of Sxl primary transcripts generates an all-or-none bistable behavior and constitutes an efficient stabilization and memorization device. The model indicates that production of a small amount of early Sxl proteins leaves the autoregulatory loop in its off state. Numerical simulations of mutant genotypes enable us to reproduce and explain the phenotypic effects of perturbations induced in the dosage of genes whose products participate in the early Sxl promoter activation.

MODELING OF PROTEIN INTERACTIONS INVOLVED IN CARDIAC TENSION DEVELOPMENT

2003 ◽  
Vol 13 (12) ◽  
pp. 3561-3578 ◽  
Author(s):  
F. B. SACHSE ◽  
K. G. GLÄNZEL ◽  
G. SEEMANN
Keyword(s):  
Steady State ◽  
Numerical Simulations ◽  
Intracellular Calcium ◽  
Hybrid Model ◽  
Protein Interactions ◽  
Experimental Studies ◽  
Quantitative Agreement ◽  
Tension Development ◽  
Cross Bridge ◽  
Configuration Changes

Modeling of protein interactions responsible for cardiac tension development can enhance the understanding of physiological and pathophysiological phenomena of the heart. Principal components of muscular tension development are the proteins actin, myosin, troponin and tropomyosin. The tension is produced by cross-bridge cycling of actin and myosin using adenosine triphosphate as energy source. The cross-bridge cycling is initiated by binding of intracellular calcium to troponin, resulting in configuration changes of tropomyosin. In this work a hybrid model of protein interactions in cardiac tension development is derived on basis of recent measurements and descriptions on protein level. Dependencies on intracellular calcium concentration, sarcomere stretch and stretch velocity as well as cooperativity mechanisms are incorporated. The model quantifies the tension development by states associated to configurations of the involved proteins. The model enables in conjunction with electrophysiological models of cardiac myocytes the reconstruction of electro-mechanical phenomena. Numerical simulations with the hybrid model were performed, which illustrated the reconstruction of steady state and length switches experiments. The steady state experiments describe the force-cytosolic [ Ca 2+] relationship in intact rat cardiac trabeculae. The length switch experiments provide data on the redevelopment of force after sudden stretch in rabbit right ventricular papillary muscles. Results of the numerical simulations show quantitative agreement with experimental studies. The hybrid model of cardiac tension development offers interfaces to further models of cardiac electro-mechanics. The hybrid model can be coupled with models of cellular electrophysiology and passive mechanics of myocardium allowing the inclusion of mechano-electrical feedback mechanisms. The hybrid model can be applied to elucidate cooperativity mechanisms, pathophysiological changes and metabolism of tension development.

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