The Experts below are selected from a list of 59388 Experts worldwide ranked by ideXlab platform
Marcelo Souza De Castro - One of the best experts on this subject based on the ideXlab platform.
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Interfacial-Tension-Force model for the wavy stratified liquid-liquid flow pattern transition: The usage of two different approaches
2016Co-Authors: Marcelo Souza De Castro, Oscar Mauricio Hernandez RodriguezAbstract:The study of the hydrodynamic stability of flow patterns is important in the design of equipment and pipelines for multiphase flows. The maintenance of a particular flow pattern becomes important in many applications, e.g., stratified flow pattern in heavy oil production avoiding the formation of emulsions because of the separation of phases and annular flow pattern in heat exchangers which increases the heat transfer coefficient. Flow maps are drawn to orientate engineers which flow pattern is present in a pipeline, for example. The ways how these flow maps are drawn have changed from totally experimental work, to phenomenological models, and then to stability analysis theories. In this work an experimental liquid-liquid flow map, with water and viscous oil as work fluids, drawn via subjective approach with high speed camera was used to compare to approaches of the same theory: the interfacial-Tension-Force model. This theory was used to drawn the wavy stratified flow pattern transition boundary. This pa...
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Interfacial-Tension-Force model for the wavy-stratified liquid–liquid flow pattern transition
International Journal of Multiphase Flow, 2014Co-Authors: Oscar Mauricio Hernandez Rodriguez, Marcelo Souza De CastroAbstract:Abstract The flow of two immiscible liquids is of common occurrence in a wide range of natural and industrial processes. The interest in liquid–liquid flow has recently increased mainly due to the petroleum industry, where oil and water are often transported together for long distances. In the current Brazilian offshore scenario, significant amount of water is being produced, and it tends to increase. The one-dimensional two-fluid model is used to model the wavy stratified liquid–liquid flow. A stability analysis is carried out, including the interfacial Tension Force and a single transition criterion is proposed. A new destabilizing term arises, which is a function of the cross-section curvature of the interface. The existence of short interfacial waves is considered and the effect of a concave or convex cross-section interface shape is included in the analysis. It is shown that the new interfacial Tension term plays an important role in regions of extreme in situ volume fractions. The kinematic wave theory is used to model the observed interfacial wave. New geometrical and kinematic wave data are used to validate the proposed model. Transition boundaries are drawn on flow maps of the superficial velocities and the agreement with present data and data from literature is encouraging. The results help to elucidate the actual nature of the typical wavy structure observed in stratified flow and can be used for the proposition of more accurate flow-pattern transition models.
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interfacial Tension Force model for the wavy stratified liquid liquid flow pattern transition
International Journal of Multiphase Flow, 2014Co-Authors: Oscar Mauricio Hernandez Rodriguez, Marcelo Souza De CastroAbstract:Abstract The flow of two immiscible liquids is of common occurrence in a wide range of natural and industrial processes. The interest in liquid–liquid flow has recently increased mainly due to the petroleum industry, where oil and water are often transported together for long distances. In the current Brazilian offshore scenario, significant amount of water is being produced, and it tends to increase. The one-dimensional two-fluid model is used to model the wavy stratified liquid–liquid flow. A stability analysis is carried out, including the interfacial Tension Force and a single transition criterion is proposed. A new destabilizing term arises, which is a function of the cross-section curvature of the interface. The existence of short interfacial waves is considered and the effect of a concave or convex cross-section interface shape is included in the analysis. It is shown that the new interfacial Tension term plays an important role in regions of extreme in situ volume fractions. The kinematic wave theory is used to model the observed interfacial wave. New geometrical and kinematic wave data are used to validate the proposed model. Transition boundaries are drawn on flow maps of the superficial velocities and the agreement with present data and data from literature is encouraging. The results help to elucidate the actual nature of the typical wavy structure observed in stratified flow and can be used for the proposition of more accurate flow-pattern transition models.
Oscar Mauricio Hernandez Rodriguez - One of the best experts on this subject based on the ideXlab platform.
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Interfacial-Tension-Force model for the wavy stratified liquid-liquid flow pattern transition: The usage of two different approaches
2016Co-Authors: Marcelo Souza De Castro, Oscar Mauricio Hernandez RodriguezAbstract:The study of the hydrodynamic stability of flow patterns is important in the design of equipment and pipelines for multiphase flows. The maintenance of a particular flow pattern becomes important in many applications, e.g., stratified flow pattern in heavy oil production avoiding the formation of emulsions because of the separation of phases and annular flow pattern in heat exchangers which increases the heat transfer coefficient. Flow maps are drawn to orientate engineers which flow pattern is present in a pipeline, for example. The ways how these flow maps are drawn have changed from totally experimental work, to phenomenological models, and then to stability analysis theories. In this work an experimental liquid-liquid flow map, with water and viscous oil as work fluids, drawn via subjective approach with high speed camera was used to compare to approaches of the same theory: the interfacial-Tension-Force model. This theory was used to drawn the wavy stratified flow pattern transition boundary. This pa...
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Interfacial-Tension-Force model for the wavy-stratified liquid–liquid flow pattern transition
International Journal of Multiphase Flow, 2014Co-Authors: Oscar Mauricio Hernandez Rodriguez, Marcelo Souza De CastroAbstract:Abstract The flow of two immiscible liquids is of common occurrence in a wide range of natural and industrial processes. The interest in liquid–liquid flow has recently increased mainly due to the petroleum industry, where oil and water are often transported together for long distances. In the current Brazilian offshore scenario, significant amount of water is being produced, and it tends to increase. The one-dimensional two-fluid model is used to model the wavy stratified liquid–liquid flow. A stability analysis is carried out, including the interfacial Tension Force and a single transition criterion is proposed. A new destabilizing term arises, which is a function of the cross-section curvature of the interface. The existence of short interfacial waves is considered and the effect of a concave or convex cross-section interface shape is included in the analysis. It is shown that the new interfacial Tension term plays an important role in regions of extreme in situ volume fractions. The kinematic wave theory is used to model the observed interfacial wave. New geometrical and kinematic wave data are used to validate the proposed model. Transition boundaries are drawn on flow maps of the superficial velocities and the agreement with present data and data from literature is encouraging. The results help to elucidate the actual nature of the typical wavy structure observed in stratified flow and can be used for the proposition of more accurate flow-pattern transition models.
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interfacial Tension Force model for the wavy stratified liquid liquid flow pattern transition
International Journal of Multiphase Flow, 2014Co-Authors: Oscar Mauricio Hernandez Rodriguez, Marcelo Souza De CastroAbstract:Abstract The flow of two immiscible liquids is of common occurrence in a wide range of natural and industrial processes. The interest in liquid–liquid flow has recently increased mainly due to the petroleum industry, where oil and water are often transported together for long distances. In the current Brazilian offshore scenario, significant amount of water is being produced, and it tends to increase. The one-dimensional two-fluid model is used to model the wavy stratified liquid–liquid flow. A stability analysis is carried out, including the interfacial Tension Force and a single transition criterion is proposed. A new destabilizing term arises, which is a function of the cross-section curvature of the interface. The existence of short interfacial waves is considered and the effect of a concave or convex cross-section interface shape is included in the analysis. It is shown that the new interfacial Tension term plays an important role in regions of extreme in situ volume fractions. The kinematic wave theory is used to model the observed interfacial wave. New geometrical and kinematic wave data are used to validate the proposed model. Transition boundaries are drawn on flow maps of the superficial velocities and the agreement with present data and data from literature is encouraging. The results help to elucidate the actual nature of the typical wavy structure observed in stratified flow and can be used for the proposition of more accurate flow-pattern transition models.
Chung Bang Yun - One of the best experts on this subject based on the ideXlab platform.
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Field application of elasto-magnetic stress sensors for monitoring of cable Tension Force in cable-stayed bridges
Smart Structures and Systems, 2013Co-Authors: Jinsuk Yim, Ming L. Wang, Sung Woo Shin, Chung Bang Yun, Hyung-jo Jung, Jeong-tae Kim, Seung-hyun EemAbstract:Recently, a novel stress sensor, which utilizes the elasto-magnetic (EM) effect of ferromagnetic materials, has been developed to measure stress in steel cables and wires. In this study, the effectiveness of this EM based stress sensors for monitoring of the cable Tension Force of a real scale cable-stayed bridge was investigated. Two EM stress sensors were installed on two selected multi-strand cables in Hwa-Myung Bridge, Busan, South Korea. Conventional lift-off test was conducted to obtain reference cable Tension Forces of two test cables. The reference Forces were used to calibrate and validate cable Tension Force measurements from the EM sensors. Tension Force variations of two test cables during the second Tensioning work on Hwa-Myung Bridge were monitored using the EM sensors. Numerical simulations were conducted to compare and verify the monitoring results. Based on the results, the effectiveness of EM sensors for accurate field monitoring of the cable Tension Force of cable-stayed bridge is discussed.
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Development of an Automated Wireless Tension Force Estimation System for Cable-stayed Bridges
Journal of Intelligent Material Systems and Structures, 2009Co-Authors: Soojin Cho, Jerome P. Lynch, Jong-jae Lee, Chung Bang YunAbstract:Cable-supported bridges rely on the use of steel cables to support the bridge deck and load on it. Cable Tension Forces are monitored during construction to assist the alignment of cables and to ensure no cables are overloaded. Given that the cables are critical load carrying elements, it is prudent to routinely monitor the levels of cable Tensions during operation. With current measurement methods being costly and labor-intensive, this article proposes an automated and low-cost wireless sensor system for continuous monitoring of the cable Tension based on the vibration signature of the cable. A vibration-based Tension Force estimation method using a peak picking algorithm is explored by embedding it in the computational core of a wireless sensor. Welch's method to average Fourier spectra from the segments of a long time history signal is employed to remove the non-stationarity of a short- duration acceleration record, which is a limit of the memory-constrained wireless sensor. A series of laboratory tests are conducted on a slender braided steel cable with a variety of cable sags and Tension Forces. Excellent agreements have been found between the actual Tensions and those estimated by the present wireless system.
Joseph B Keller - One of the best experts on this subject based on the ideXlab platform.
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surface Tension Force on a partly submerged body
Physics of Fluids, 1998Co-Authors: Joseph B KellerAbstract:The vertical component of the surface Tension Force on a body partly submerged in a liquid is shown to equal the weight of liquid displaced by the meniscus. It is upward if the meniscus is depressed and downward if the meniscus is elevated. Previously this was known for vertical axially symmetric bodies and for two-dimensional vertical plates. The vertical component of the pressure Force on the body is shown to equal the weight of liquid which would fill the volume bounded by the wetted surface of the body, a vertical cylinder through the waterline, and the original horizontal free surface.
Shi Shu - One of the best experts on this subject based on the ideXlab platform.
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A free energy-based surface Tension Force model for simulation of multiphase flows by level-set method
Journal of Computational Physics, 2017Co-Authors: Haizhuan Yuan, Zhen Chen, Chang Shu, Y. Wang, Xiao-dong Niu, Shi ShuAbstract:In this paper, a free energy-based surface Tension Force (FESF) model is presented for accurately resolving the surface Tension Force in numerical simulation of multiphase flows by the level set method. By using the analytical form of order parameter along the normal direction to the interface in the phase-field method and the free energy principle, FESF model offers an explicit and analytical formulation for the surface Tension Force. The only variable in this formulation is the normal distance to the interface, which can be substituted by the distance function solved by the level set method. On one hand, as compared to conventional continuum surface Force (CSF) model in the level set method, FESF model introduces no regularized delta function, due to which it suffers less from numerical diffusions and performs better in mass conservation. On the other hand, as compared to the phase field surface Tension Force (PFSF) model, the evaluation of surface Tension Force in FESF model is based on an analytical approach rather than numerical approximations of spatial derivatives. Therefore, better numerical stability and higher accuracy can be expected. Various numerical examples are tested to validate the robustness of the proposed FESF model. It turns out that FESF model performs better than CSF model and PFSF model in terms of accuracy, stability, convergence speed and mass conservation. It is also shown in numerical tests that FESF model can effectively simulate problems with high density/viscosity ratio, high Reynolds number and severe topological interfacial changes. A free energy-based surface Tension Force (FESF) model is proposed for simulation of multiphase flows by level set method.The proposed model computes the surface Tension Force by an explicit form.The proposed model outperforms the existing models in terms of accuracy, stability, convergence speed and mass conservation.The proposed model can effectively simulate multiphase flows.
