Computational Modeling of the Collapse of a Liquid Column Over an Obstacle and Experimental Validation

2009 ◽  
Vol 76 (2) ◽  
Author(s):  
Marcela A. Cruchaga ◽  
Diego J. Celentano ◽  
Tayfun E. Tezduyar
Keyword(s):  
Aspect Ratio ◽  
Computational Modeling ◽  
Water Column ◽  
Physical Model ◽  
Experimental Validation ◽  
Moving Interface ◽  
Numerical Predictions ◽  
Air Interface ◽  
Control Section ◽  
The Right

We present the numerical and experimental analyses of the collapse of a water column over an obstacle. The physical model consists of a water column initially confined by a closed gate inside a glass box. An obstacle is placed between the gate and the right wall of the box, inside the initially unfilled zone. Once the gate is opened, the liquid spreads in the container and over the obstacle. Measurements of the liquid height along the walls and a middle control section are obtained from videos. The computational modeling is carried out using a moving interface technique, namely, the edge-tracked interface locator technique, to calculate the evolution of the water-air interface. The analysis involves a water-column aspect ratio of 2, with different obstacle geometries. The numerical predictions agree reasonably well with the experimental trends.

Symmetric Single Rod Cylinders With Variable Piston Area? A Comprehensive Approach to the Right Solution

2018 ◽  
Author(s):  
Giacomo Kolks ◽  
Jürgen Weber
Keyword(s):  
Experimental Validation ◽  
Design Space ◽  
Solution Space ◽  
Hydraulic Cylinder ◽  
Load Cycle ◽  
Displacement Control ◽  
Comprehensive Description ◽  
Subsequent Step ◽  
Variable Displacement ◽  
The Right

In contrast to rotational hydraulic displacement units, such as pumps or motors, conventional hydraulic cylinder actuators do not allow a continuous variation of their displacement quantity: the piston area is regarded constant. In order to adapt to varying load and velocity requirements in a load cycle under torque restrictions of the driving motor, cylinder drives often implement pumps with variable displacement. In this paper, cylinders with discretely variable effective piston area by means of variable circuitry of multi-chamber cylinders are discussed. Hydraulic symmetry or constant asymmetry of the hydraulic cylinder are traits of the cylinder that are required to fit the cylinder to pump structures for closed-circuit displacement control, as given in electro-hydrostatic compact drives (ECD). A methodology to generate all possible solutions of variable area cylinders under the constraint of ECD requirements is proposed. A comprehensive description of the solution space is given, based on combinatorics and solution of equation systems. The methodology dealing with abstract cylinder areas is backed up by a general approach to describe the mechanical cylinder design space to combine multiple cylinder areas in one structural unit. Examples for design of three and four area cylinders are given and results are discussed. The paper concludes with the development of a demonstrator design to allow experimental validation in a subsequent step.

scholarly journals Reduction in Current THD of Grid Parallel Inverters Using Randomized PR Control

2017 ◽  
Vol 8 (1) ◽  
pp. 290 ◽  
Author(s):  
S. Salimin ◽  
S. A. Zulkifli ◽  
M. Armstrong
Keyword(s):  
Power Factor ◽  
Experimental Validation ◽  
Switching Scheme ◽  
Output Current ◽  
Unity Power Factor ◽  
Current Harmonics ◽  
Passive Filter ◽  
Current Controller ◽  
The Right ◽  
Inverter Topology

In grid connected system, unity power factor current injection into the grid is vital. This can be achieved by choosing the right inverter topology, passive filter components, current controllers, and PWM switching scheme. This paper compares the output current harmonics profile between when using the conventional proportional resonant (PR) current controller and when using the modified PR current controller. By applying the latter technique, via experimental validation using TMS320F2812, the THD of the injected grid current in a parallel connected inverters system is improved.

Heatline and Massline Visualization of Hydromagnetic Double Diffusive Convective Flow of Nanofluid Within a Porous Trapezoidal Cavity

2021 ◽  
Vol 10 (2) ◽  
pp. 270-284
Author(s):  
Bikash C. Saha ◽  
T. R. Mahapatra ◽  
Dulal Pal
Keyword(s):  
Aspect Ratio ◽  
Convective Flow ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Darcy Number ◽  
Temperature Fields ◽  
Computational Domain ◽  
Aspect Ratios ◽  
Numerical Predictions ◽  
Double Diffusive

Double diffusive convective flow of nanofluid within a porous trapezoidal cavity of various aspect ratios consisting of Al2O3 nanoparticle in the presence of applied magnetic field in the direction perpendicular to the parallel top and bottom walls is analysed. The side walls of the cavity are maintained at constant temperature and concentration while its horizontal walls are insulated and impermeable. The irregular physical domain of the problem is transformed to a regular unit square computational domain. The governing equations have been solved by second order of finite difference method (FDM). Based upon numerical predictions, the effects of pertinent parameters such as Rayleigh number, Darcy number, aspect ratio, solid volume fraction and inclination angle on the flow and temperature fields and the heat transfer performance of the enclosure are examined. It is found that the intensity of heat and mass transfer increases with the increase in the Darcy number and aspect ratio. It is also observed that as the solid volume fraction increases there is increase in the average Nusselt number but reverse effect is observed on the average Sherwood number.

scholarly journals Metformin Is a Direct SIRT1-Activating Compound: Computational Modeling and Experimental Validation

2018 ◽  
Vol 9 ◽  
Author(s):  
Elisabet Cuyàs ◽  
Sara Verdura ◽  
Laura Llorach-Parés ◽  
Salvador Fernández-Arroyo ◽  
Jorge Joven ◽  
...  
Keyword(s):  
Computational Modeling ◽  
Experimental Validation

COMPUTATIONAL ANALYSIS OF HEAT AND MASS TRANSPORT IN CHARACTERISTIC DETAIL OF INTERIOR THERMAL INSULATION SYSTEM

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Jiří Maděra ◽  
Jan Kočí ◽  
Václav Kočí
Keyword(s):  
Computational Modeling ◽  
Thermal Insulation ◽  
System Application ◽  
Building Materials ◽  
Wood Fiber ◽  
Mineral Wool ◽  
Point Of View ◽  
Insulation Materials ◽  
Beneficial Effects ◽  
The Right

Computational modeling represents useful tool for the assessment of newly designed or refurbished building materials and structures. Especially, when complex buildings elements need to be assessed from a hygrothermal point of view, the computational modeling is the right approach with desired power and accuracy. In this paper a historical wall element is investigated using two-dimensional simulation in order to study the effect of application of several insulation materials in various scenarios. In total two insulation materials are investigated (mineral wool, wood fiber boards) that are applied in three different scenarios. All simulations are performed under real climatic load. The results of the computational simulations reveal potential weak points in system application and can provide engineers and designers with valuable recommendations and practical information. The best results were obtained for thermal insulation from mineral wool. On the other hand, an improper system application can lead to a significant devaluation of the beneficial effects on the thermal performance of the studied brick element.

scholarly journals Is Psychology Headed in the Right Direction? Yes, No, and Maybe

2017 ◽  
Vol 12 (4) ◽  
pp. 656-659 ◽  
Author(s):  
Carol S. Dweck
Keyword(s):  
Computational Modeling ◽  
Cognitive Science ◽  
Developmental Psychology ◽  
Social Issues ◽  
Interdisciplinary Nature ◽  
Exciting Time ◽  
The Right

In this piece, I first celebrate the growing contribution of psychology to the understanding and solution of pressing social issues. Then, despite these exciting developments, I worry about whether we have created a field that our students want to spend their lives in, and I suggest concerns that might fruitfully be addressed. Finally, I worry about the potential fragmentation of psychology and applaud programs of research that have shown the unique and important contributions to be made when the methods and perspectives of neuroscience, cognitive science, and computational modeling are integrated with those of social, personality, and developmental psychology. In sum, although this is an exciting time for our field, we can do more to ensure its vigor and its truly interdisciplinary nature as we move forward.

The Natural Vacuum Desalination Technology in Seawater Desalination

2014 ◽  
Vol 675-677 ◽  
pp. 851-855 ◽  
Author(s):  
Xiao Hua Liu ◽  
Xin Chun Zhang ◽  
Ya Qin Fang ◽  
Ming Ming Zhu
Keyword(s):  
Low Temperature ◽  
Water Column ◽  
Physical Model ◽  
Future Development ◽  
Atmospheric Pressure ◽  
High Water ◽  
Seawater Desalination ◽  
Different Types ◽  
Desalination Technology

Seawater desalination technology is an important way to solve the freshwater shortage problem. Natural vacuum desalination (NVD) technology generates very low pressure environment in the headspace of 10 meters high water column. The weight of the water column is balanced by atmospheric pressure, and low-temperature desalination proceeds in the headspace. NVD technology drives the desalination process without any mechanical pumping, and requires relatively inferior quality of device material and simple structures. In this paper, the basic theory of NVD technology is introduced and physical model is described. Research progresses of different types of NVD technologies are summarized, and the method of increasing freshwater production is pointed out. This paper also illustrates the outlook on future development of NVD technology.

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