scholarly journals Simulation of Floating Debris in Violent Shallow Flows

10.29007/xw2s ◽  
2018 ◽  
Author(s):  
Yan Xiong ◽  
Samantha Mahaffey ◽  
Qiuhua Liang
Keyword(s):  
Laboratory Experiments ◽  
Coupled Model ◽  
Storm Surges ◽  
Element Model ◽  
Shock Capturing ◽  
Hydrodynamic Characteristics ◽  
Experimental Measurements ◽  
Shallow Flows ◽  
Complex Fluid ◽  
Fully Coupled

Storm surge and tsunami may induce violent shallow flows and carry dense debris, causing tremendous damage to human lives, buildings and structures. This work presents a series of laboratory experiments to investigate the debris movement in the extreme flows. Subsequently, a new modeling tool featured with a finite volume shock-capturing hydrodynamic model fully coupled with a discrete element model is introduced. A new coupling method totally depending on the hydrodynamic characteristics is proposed to simulate the complex debris-enriched floods induced by tsunamis or storm surges. The experimental measurements are used to validate the reliability of the coupled model. The numerical results agree satisfactorily with the experimental measurements, demonstrating the model’s capability in simulating the complex fluid-debris interactions induced by violent shallow flows.

scholarly journals Simulation thermomécanique du soudage par friction-malaxage

2007 ◽  
pp. 865-887
Author(s):  
Eric Feulvarch ◽  
Frédéric Boitout ◽  
Jean-Michel Bergheau
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Welding Process ◽  
Coupled Model ◽  
Mass Conservation ◽  
Element Model ◽  
Friction Stir ◽  
Stress Equilibrium ◽  
Mechanical Dissipation ◽  
Fully Coupled

Friction Stir Welding is a welding process where the heat generation is provided by the mechanical dissipation due to the deformations and the friction between the tool and the sheets. This paper describes a finite element model to simulate the heating phenomenon during the steady-state of the process. The stress equilibrium, the energy conservation and the mass conservation are studied in a fully coupled model using a tetrahedral finite element. An example is presented for an aluminium alloy 7075.

Rotordynamic Analysis of a Large Industrial Turbo-Compressor Including Finite Element Substructure Modeling

2006 ◽  
Author(s):  
J. Jeffrey Moore ◽  
Giuseppe Vannini ◽  
Massimo Camatti ◽  
Paolo Bianchi
Keyword(s):  
Finite Element ◽  
Transfer Function ◽  
Transfer Functions ◽  
Three Dimensional ◽  
Coupled Model ◽  
Element Model ◽  
7Th Edition ◽  
Curve Fit ◽  
Turbo Compressor ◽  
Fully Coupled

A rotordynamic analysis of a large turbo-compressor that models both the casing and supports along with the rotor-bearing system was performed. A three-dimensional (3-D) finite element model of the casing captures the intricate details of the casing and support structure. Two approaches are presented, including development of transfer functions of the casing and foundation, as well as a fully coupled rotor-casing-foundation model. The effect of bearing support compliance is captured, as well as the influence of casing modes on the rotor response. The first approach generates frequency response functions (FRF’s) from the finite element case model at the bearing support locations. A high-order polynomial in numerator-denominator transfer function format is generated from a curve-fit of the FRF. These transfer functions are then incorporated into the rotordynamics model. The second approach is a fully coupled rotor and casing model that is solved together. An unbalance response calculation is performed in both cases to predict the resulting rotor critical speeds and response of the casing modes. The effect of the compressor case and supports caused the second critical speed to drop to a value close to the operating speed and not compliant with API 617 7th edition requirements. A combination of rotor, journal bearing, casing, and support modifications resulted in a satisfactory and API compliant solution. The results of the fully coupled model validated the transfer function approach.

Rotordynamic Analysis of a Large Industrial Turbocompressor Including Finite Element Substructure Modeling

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
J. Jeffrey Moore ◽  
Giuseppe Vannini ◽  
Massimo Camatti ◽  
Paolo Bianchi
Keyword(s):  
Finite Element ◽  
Transfer Function ◽  
Transfer Functions ◽  
Coupled Model ◽  
Element Model ◽  
American Petroleum Institute ◽  
7Th Edition ◽  
Curve Fit ◽  
Rotor Journal ◽  
Fully Coupled

A rotordynamic analysis of a large turbocompressor that models both the casing and supports along with the rotor-bearing system was performed. A 3D finite element model of the casing captures the intricate details of the casing and support structure. Two approaches are presented, including development of transfer functions of the casing and foundation, as well as a fully coupled rotor-casing-foundation model. The effect of bearing support compliance is captured, as well as the influence of casing modes on the rotor response. The first approach generates frequency response functions (FRFs) from the finite element case model at the bearing support locations. A high-order polynomial in numerator-denominator transfer function format is generated from a curve fit of the FRF. These transfer functions are then incorporated into the rotordynamics model. The second approach is a fully coupled rotor and casing model that is solved together. An unbalance response calculation is performed in both cases to predict the resulting rotor critical speeds and response of the casing modes. The effect of the compressor case and supports caused the second critical speed to drop to a value close to the operating speed and not compliant with the requirements of the American Petroleum Institute (API) specification 617 7th edition. A combination of rotor, journal bearing, casing, and support modifications resulted in a satisfactory and API compliant solution. The results of the fully coupled model validated the transfer function approach.

scholarly journals Fully Coupled Model for Frequency Response Simulation of Miniaturized Cantilever-Based Photoacoustic Gas Sensors

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4772 ◽  
Author(s):  
Sheng Zhou
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Frequency Response ◽  
Gas Sensors ◽  
Pressure Transducer ◽  
Coupled Model ◽  
Element Model ◽  
Radiation Absorption ◽  
Viscous Damping ◽  
Fully Coupled

To support the development of miniaturized photoacoustic gas sensors, a fully coupled finite element model for a frequency response simulation of cantilever-based photoacoustic gas sensors is introduced in this paper. The model covers the whole photoacoustic process from radiation absorption to pressure transducer vibration, and considers viscous damping loss. After validation with experimental data, the model was further applied to evaluate the possibility of further optimization and miniaturization of a previously reported sensor design.

scholarly journals Assessing the Potential Highest Storm Tide Hazard in Taiwan Based on 40-Year Historical Typhoon Surge Hindcasting

Atmosphere ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 346 ◽  
Author(s):  
Yi-Chiang Yu ◽  
Hongey Chen ◽  
Hung-Ju Shih ◽  
Chih-Hsin Chang ◽  
Shih-Chun Hsiao ◽  
...  
Keyword(s):  
Coupled Model ◽  
Storm Surges ◽  
Storm Tide ◽  
Astronomical Tide ◽  
Individual Potential ◽  
Hazard Level ◽  
The Individual ◽  
Central Weather Bureau ◽  
Fully Coupled

Typhoon-induced storm surges are catastrophic disasters in coastal areas worldwide, although typhoon surges are not extremely high in Taiwan. However, the rising water level around an estuary could be a block that obstructs the flow of water away from the estuary and indirectly forms an overflow in the middle or lower reaches of a river if the occurrence of the highest storm surge (HSS) coincides with the highest astronomical tide (HAT). Therefore, assessing the highest storm tide (HST, a combination of the HSS and HAT) hazard level along the coast of Taiwan is particularly important to an early warning of riverine inundation. This study hindcasted the storm surges of 122 historical typhoon events from 1979 to 2018 using a high-resolution, unstructured-grid, surge-wave fully coupled model and a hybrid typhoon wind model. The long-term recording measurements at 28 tide-measuring stations around Taiwan were used to analyze the HAT characteristics. The hindcasted HSSs of each typhoon category (the Central Weather Bureau of Taiwan classified typhoon events into nine categories according to the typhoon’s track) were extracted and superposed on the HATs to produce the individual potential HST hazard maps. Each map was classified into six hazard levels (I to VI). Finally, a comprehensive potential HST hazard map was created based on the superposition of the HSSs from 122 typhoon events and HATs.

Finite Element Simulation of Tire-Rim Interface

1989 ◽  
Vol 17 (4) ◽  
pp. 305-325 ◽  
Author(s):  
N. T. Tseng ◽  
R. G. Pelle ◽  
J. P. Chang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Simulation ◽  
Contact Pressure ◽  
Element Model ◽  
Experimental Measurements ◽  
Inflation Pressure ◽  
Interference Fit ◽  
Element Simulation ◽  
Rubber Composite

Abstract A finite element model was developed to simulate the tire-rim interface. Elastomers were modeled by nonlinear incompressible elements, whereas plies were simulated by cord-rubber composite elements. Gap elements were used to simulate the opening between tire and rim at zero inflation pressure. This opening closed when the inflation pressure was increased gradually. The predicted distribution of contact pressure at the tire-rim interface agreed very well with the available experimental measurements. Several variations of the tire-rim interference fit were analyzed.

Stress self-sensing in Amplified Piezoelectric Actuators through a fully-coupled model of hysteresis

2020 ◽  
Vol 579 ◽  
pp. 411894
Author(s):  
Valerio Apicella ◽  
Carmine Stefano Clemente ◽  
Daniele Davino ◽  
Damiano Leone ◽  
Ciro Visone
Keyword(s):  
Coupled Model ◽  
Piezoelectric Actuators ◽  
Fully Coupled

Theoretical analysis of a rolling-sliding elastohydrodynamic lubrication line contact with a subsurface inclusion

2019 ◽  
Vol 233 (8) ◽  
pp. 1197-1207
Author(s):  
Armando Félix Quiñonez ◽  
Guillermo E Morales Espejel
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Element Model ◽  
Von Mises Stress ◽  
Transient Effects ◽  
Mean Velocity ◽  
The Matrix ◽  
Soft Inclusion ◽  
The Mean ◽  
Von Mises ◽  
Fully Coupled

This work investigates the transient effects of a single subsurface inclusion over the pressure, film thickness, and von Mises stress in a line elastohydrodynamic lubrication contact. Results are obtained with a fully-coupled finite element model for either a stiff or a soft inclusion moving at the speed of the surface. Two cases analyzed consider the inclusion moving either at the same speed as the mean velocity of the lubricant or moving slower. Two additional cases investigate reducing either the size of the inclusion or its stiffness differential with respect to the matrix. It is shown that the well-known two-wave elastohydrodynamic lubrication mechanism induced by surface features is also applicable to the inclusions. Also, that the effects of the inclusion become weaker both when its size is reduced and when its stiffness approaches that of the matrix. A direct comparison with predictions by the semi-analytical model of Morales-Espejel et al. ( Proc IMechE, Part J: J Engineering Tribology 2017; 231) shows reasonable qualitative agreement. Quantitatively some differences are observed which, after accounting for the semi-analytical model's simplicity, physical agreement, and computational efficiency, may then be considered as reasonable for engineering applications.

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