Quasi-3D two-phase model for dam-break flow over movable bed based on a non-hydrostatic depth-integrated model with a dynamic rough wall law

2019 ◽  
Vol 129 ◽  
pp. 311-327 ◽  
Author(s):  
Tatsuhiko Uchida ◽  
Shoji Fukuoka
Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 669
Author(s):  
Kangxin Chen ◽  
Houfa Shen

Macrosegregation, a serious defect formed during the solidification of steel ingots, impairs the performance of the final components. To predict macrosegregation caused by thermal-solutal convection and solid deformation, a volume-averaged single-phase/two-phase integrated model is developed. During the deformation stage, the two-phase model coupling the solid deformation and liquid flow in the mushy zone is utilized. Before or after the deformation stage, the motion of the solid phase is neglected, and the single-phase model is solved. A 450 kg steel ingot punching test is considered for application. The results show that when the solid shell of the ingot is being punched, the solid phase in the mushy core at punching height is compressed, and a relative liquid flow is induced. This in turn causes a transition of positive segregation to negative segregation in the compressed mushy core of the ingot. According to numerical sensitivity tests of different punching parameters, as the punching start time and punching velocity increase, the effect of punching on macrosegregation will be smaller. It is demonstrated that the single-phase/two-phase integrated model can predict macrosegregation in the steel ingots which are deformed during solidification.


2014 ◽  
Vol 29 (3) ◽  
pp. 344-356 ◽  
Author(s):  
Seyedeh Leila RAZAVITOOSI ◽  
Seyed Ali AYYOUBZADEH ◽  
Alireza VALIZADEH
Keyword(s):  

2012 ◽  
Vol 256-259 ◽  
pp. 2621-2624
Author(s):  
W.L. Wei ◽  
X.J. Zhao ◽  
Y. L. Liu

This paper is concerned with a gas-liquid two-phase model combining with the k–ε turbulent model for numerical simulation of 3D flood waves due to complete or partial dam-break. The flow equations are solved with the finite volume method and solved by the pressure-correction algorithm of the SIMPLE-type. The free fluid surface is simulated by the the volume of fluid(VOF) method. The comparisons with other numerical results show that the proposed method is accurate, reliable and effective in simulation of dam-break flood waves.


2016 ◽  
pp. 522-527
Author(s):  
J. Zhao ◽  
I. Özgen ◽  
R. Hinkelmann ◽  
F. Simons ◽  
D. Liang

2020 ◽  
Author(s):  
Sangyoung Son ◽  
Taehwa Jung ◽  
Dae-Hong Kim ◽  
Hyun-Doug Yoon

<p>At the nearshore area, strong and energetic flow fields can be easily formed during the tsunami event and it is hence expected coastal morphology is significantly affected by complex tsunami-induced current. In this study, the morphological changes by tsunami impacts on the US west coasts were investigated by numerical modeling. Firstly, we introduced a developed numerical model for calculating morphological changes by the tsunami wave, which incorporates a set of sub-models; hydrodynamics, sediment transport and morphological evolution models. The fully nonlinear Boussinesq-type model was adopted in the hydrodynamics calculations aiming at the better recreation of nearshore current fields which easily develop into turbulent flows due to various types of sources (e.g., wave-breaking). Then, the benchmark tests of one-dimensional or two-dimensional sedimentation problems were performed for validation; dam-break flow over the movable bed, breaking solitary waves over a sloping beach, partially breached dam-break flow over the mobile bed, and dam-break flows over a movable bed with a sudden enlargement. Calculated results revealed good agreement with the experimental records when a reasonable parameter has been chosen for closure models. As a real-scale application of the model, the 2011 Tohoku-Oki tsunami event was attempted, which subsequently presented a good prediction of tsunami-generated scouring and deposition in harbors. It was also confirmed that strong currents were successfully generated through the model, causing severe depth changes through the sedimentation process. To provide a rough guide for prospective users, we also performed several types of sensitivity tests on many parameters involved in the model</p>


1968 ◽  
Vol 78 (3, Pt.1) ◽  
pp. 359-368 ◽  
Author(s):  
William F. Prokasy ◽  
Martha A. Harsanyi

1997 ◽  
Vol 35 (7) ◽  
pp. 139-145 ◽  
Author(s):  
Jiann-Yuan Ding ◽  
Shian-Chee Wu

The objective of this study is to quantify the effects of humic acid solution infiltration on the transport of organochlorine pesticides (OCPs) in soil columns using a three-phase transport model. From experimental results, it is found that the dissolved organic carbon enhances the transport of OCPs in the soil columns. In the OCPs-only column, the concentration profiles of OCPs can be simulated well using a two-phase transport model with numerical method or analytical solution. In the OCPs-DOC column, the migrations of aldrin, DDT and its daughter compounds are faster than those in the OCPs-only column. The simulation with the three-phase model is more accurate than that with the two-phase model. In addition, significant decrease of the fluid pore velocities of the OCPs-DOC column was found. When DOC leachate is applied for remediation of soil or groundwater pollution, the decrease of mean pore velocities will be a crucial affecting factor.


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