Numerical and Experimental Evaluation of the Viscous Damping in a Wellbay

2004 ◽  
Author(s):  
C. Maisondieu ◽  
O. Kimmoun ◽  
C. De Joue¨tte ◽  
L. Gentaz
Keyword(s):  
Energy Dissipation ◽  
Viscous Fluid ◽  
Experimental Evaluation ◽  
Numerical Models ◽  
Velocity Fields ◽  
Viscous Damping ◽  
Damping Coefficients ◽  
Comparison Of Results ◽  
Water Elevation ◽  
Good Agreement

Flow viscous damping and energy dissipation around the keels in a wellbay are experimentally and numerically investigated. Experiments have been carried out using a U-shape tube. Damping coefficients are evaluated from water elevation measurements. Computations are also performed using two different numerical models under viscous fluid assumption. Comparison of results shows good agreement on both drag coefficients evaluation and velocity fields.

scholarly journals Modeling of Spray Combustion with a Steady Laminar Flamelet Model in an Aeroengine Combustion Chamber Based on OpenFOAM

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Yinli Xiao ◽  
Zupeng Wang ◽  
Zhengxin Lai ◽  
Wenyan Song
Keyword(s):  
Combustion Chamber ◽  
High Performance ◽  
Numerical Models ◽  
Spray Combustion ◽  
Combustion Chambers ◽  
Flamelet Model ◽  
Steady Laminar ◽  
Good Agreement ◽  
Laminar Flamelet ◽  
Laminar Flamelet Model

The development of high-performance aeroengine combustion chambers strongly depends on the accuracy and reliability of efficient numerical models. In the present work, a reacting solver with a steady laminar flamelet model and spray model has been developed in OpenFOAM and the solver details are presented. The solver is firstly validated by Sandia/ETH-Zurich flames. Furthermore, it is used to simulate nonpremixed kerosene/air spray combustion in an aeroengine combustion chamber with the RANS method. A comparison with available experimental data shows good agreement and validates the capability of the new developed solver in OpenFOAM.

Long-term thermal two- and three-dimensional analysis of roller compacted concrete dams supported by monitoring verification

2010 ◽  
Vol 37 (4) ◽  
pp. 600-610 ◽  
Author(s):  
Vladan Kuzmanovic ◽  
Ljubodrag Savic ◽  
John Stefanakos
Keyword(s):  
Thermal Analysis ◽  
Boundary Conditions ◽  
Thermal Field ◽  
Numerical Models ◽  
Three Dimensional ◽  
Roller Compacted Concrete ◽  
Rcc Dam ◽  
Field Investigations ◽  
Good Agreement

This paper presents two-dimensional (2D) and three-dimensional (3D) numerical models for unsteady phased thermal analysis of RCC dams. The time evolution of a thermal field has been modeled using the actual dam shape, RCC technology and the adequate description of material properties. Model calibration and verification has been done based on the field investigations of the Platanovryssi dam, the highest RCC dam in Europe. The results of a long-term thermal analysis, with actual initial and boundary conditions, have shown a good agreement with the observed temperatures. The influence of relevant parameters on the thermal field of RCC dams has been analyzed. It is concluded that the 2D model is appropriate for the thermal phased analysis, and that the boundary conditions and the mixture properties are the most influential on the RCC dam thermal behavior.

Calculation of tunnel wall interference from wall-pressure measurements

1988 ◽  
Vol 92 (911) ◽  
pp. 36-53 ◽  
Author(s):  
P. R. Ashill ◽  
R. F. A. Keating
Keyword(s):  
Experimental Evaluation ◽  
Solid Wall ◽  
Wall Pressure ◽  
Wind Tunnels ◽  
Pressure Measurements ◽  
Complex Flows ◽  
Tunnel Wall ◽  
Model Flow ◽  
Good Agreement

Summary A method is described for calculating wall interference in solid-wall wind tunnels from measurements of static pressures at the walls. Since it does not require a simulation of the model flow, the technique is particularly suited to determining wall interference for complex flows such as those over VSTOL aircraft, helicopters and bluff shapes (e.g. cars and trucks). An experimental evaluation shows that the method gives wall-induced velocities which are in good agreement with those of existing methods in cases where these techniques are valid, and illustrates its effectiveness for inclined jets which are not readily modelled.

scholarly journals Modular crawling robots using soft pneumatic actuators

2020 ◽  
Author(s):  
Nianfeng Wang ◽  
Bicheng Chen ◽  
Xiandong Ge ◽  
Xianmin Zhang ◽  
Wenbin Wang
Keyword(s):  
3D Printing ◽  
Numerical Models ◽  
Pneumatic Actuators ◽  
Axial Elongation ◽  
Control Schemes ◽  
Good Agreement

AbstractCrawling robots have elicited much attention in recent years due to their stable and efficient locomotion. In this work, several crawling robots are developed using two types of soft pneumatic actuators (SPAs), namely, an axial elongation SPA and a dual bending SPA. By constraining the deformation of the elastomeric chamber, the SPAs realize their prescribed motions, and the deformations subjected to pressures are characterized with numerical models. Experiments are performed for verification, and the results show good agreement. The SPAs are fabricated by casting and developed into crawling robots with 3D-printing connectors. Control schemes are presented, and crawling tests are performed. The speeds predicted by the numerical models agree well with the speeds in the experiments.

PRELIMINARY STUDY ON NOVEL BEAM-TO-COLUMN CONNECTION BASED ON SMA PLATE

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Michael CH Yam ◽  
Ke Ke ◽  
Ping Zhang ◽  
Qingyang Zhao
Keyword(s):  
Friction Coefficient ◽  
Energy Dissipation ◽  
Numerical Study ◽  
Numerical Models ◽  
Numerical Technique ◽  
The Self ◽  
Hysteretic Behavior ◽  
The Novel ◽  
Energy Dissipation Capacity ◽  
Preliminary Study

A novel beam-to-column connection equipped with shape memory alloy (SMA) plates has been proposed to realize resilient performance under low-to-medium seismic actions. In this conference paper, the detailed 3D numerical technique calibrated by the previous paper is adopted to examine the hysteretic behavior of the novel connection. A parametric study covering a reasonable range of parameters including the thickness of the SMA plate, friction coefficient between SMA plate and beam flange and pre-load of the bolt was carried out and the influence of the parameters was characterized. In addition, the effect of the SMA Belleville washer on the connection performance was also studied. The results of the numerical study showed that the initial connection stiffness and the energy-dissipation capacity of the novel connection can be enhanced with the increase of the thickness of the SMA plate. In addition, the initial connection stiffness and energy-dissipation behavior of the novel connection can be improved by increasing the friction coefficient or pre-load of bolts, whereas the increased friction level could compromise the self-centering behavior of the connection. The hysteretic curves of the numerical models of the connection also implied that the SMA washers may contribute to optimizing the connection behavior by increasing the connection stiffness and energy-dissipation capacity without sacrificing the self-centering behavior.

THE EFFECTS OF HALL CURRENT ON THE FLOW DUE TO THE OSCILLATING ROTATING POROUS DISK WITH A VISCOUS FLUID AT INFINITY: GRAPHICAL SOLUTIONS USING MATLAB

2021 ◽  
Vol 10 (5) ◽  
pp. 2491-2511
Author(s):  
R. Lakshmi ◽  
A. Santhakumari
Keyword(s):  
Viscous Fluid ◽  
Closed Form ◽  
Hall Current ◽  
Velocity Fields ◽  
Governing Equations ◽  
Porous Disk ◽  
Suction And Blowing

The flow due to the oscillating rotating porous disk with a viscous fluid at infinity is studied under the influence of Hall current. Governing equations are implied with reasonable approximations and solved analytically to get the expressions for the velocity fields in closed form. Graphical results are presented for the velocity components for various values of parameters namely, the Hall, suction and blowing through MATLAB and a discussion is provided. It is important to note that presented results are valid for all values of the frequencies.

scholarly journals Development Behavior for Post-Tensioned Self-Centering Steel Connection under Cyclic Loading

2017 ◽  
Vol 3 (3) ◽  
pp. 152-159
Author(s):  
Ahmadreza Torabipour ◽  
M. R. Shiravand
Keyword(s):  
Energy Dissipation ◽  
Numerical Models ◽  
Perfect Match ◽  
High Strength ◽  
Relative Displacement ◽  
Initial Stiffness ◽  
Validation Parameters ◽  
Steel Connection ◽  
Energy Dissipation Capacity ◽  
Post Tensioned

One of the newest steel beam-column joints to replace conventional welded connections, post-tensioned connection steel is with the upper and lower angles. In this connection are high-strength steel strands that parallel beam web and angles between beams and column. Actually high resistance strands and upper and lower angles respectively are provider centralization properties and energy dissipation capacity of the connection. The benefits of post-tensioned steel can be used in connection with the centralization and lack of relative displacement (drift) persistent, stay elastic core components such as connecting beams, columns and fountains connection, appropriate initial stiffness and joint manufacture with materials and traditional skills. . In this study, numerical modelling in Abaqus software, the results of the analysis were compared with the results of laboratory samples and the results showed that the two together are a perfect match. After validation, parameters influential centrist connection then pulled the thick angles in three numerical models were evaluated.  The results show that by increasing the thickness of the angles, increase energy dissipation capacity and ductility connection and the β₁ value does not experience tangible changes with changes in angle thickness.

scholarly journals Comparative Analysis of the Energy Dissipation of Steel Buildings with Concentric and Eccentric Braces

2015 ◽  
Vol 9 (1) ◽  
pp. 295-307 ◽  
Author(s):  
Edelis del V. Marquez A. ◽  
William Lobo-Q ◽  
Juan C. Vielma
Keyword(s):  
Energy Dissipation ◽  
Shear Failure ◽  
Numerical Models ◽  
Deformation Energy ◽  
Seismic Zone ◽  
Deformation Capacity ◽  
Building Structures ◽  
Steel Buildings ◽  
High Deformation ◽  
Energy Dissipation Capacity

A comparative study has been done to analyze the behavior of regular steel building structures of 4, 6, 8 and 10 stories, located in seismic zone 5 and soil type S1. The structures were upgraded with different brace configurations according to current Venezuelan codes. A total number of 24 numerical models were analyzed considering non-linear static and incremental dynamic analysis (IDA). The buildings were initially designed as moment resisting frames, and upgraded with six different bracing configurations: concentric braces in “X” and inverted “V”; eccentric braces inverted "V" with horizontal links, inverted “Y” and “X” with vertical links. Short length links were used to ensure a shear failure. The used methodology is based on obtaining the capacity, IDA curves, and bilinear approximations of these curves that allow the determination of yield and ultimate capacity points, in order to estimate important parameters of seismic response: overstrength and ductility; and considering these areas under the curves to estimate elastic deformation energy, energy dissipated by hysteretic damping and equivalent damping. According to the results, the cases with no brace enhancement showed the lowest lateral strength and lateral stiffness and high deformation capacity. On the other hand, the concentric bracing cases, resulted with the highest stiffness and strength and the lowest deformation capacity, therefore they have low ductility and energy dissipation capacity under seismic loading. Structures with links showed intermediate stiffness and strengths, resulting in the best performance in terms of ductility and energy dissipation capacity. The present study provides a better understanding of the benefits of eccentrically braced systems.

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