scholarly journals Monolithic Solvers for Incompressible Two-Phase Flows at Large Density and Viscosity Ratios

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 23
Author(s):  
Mohamed El Ouafa ◽  
Stephane Vincent ◽  
Vincent Le Chenadec
Keyword(s):  
Augmented Lagrangian ◽  
Incompressible Flows ◽  
Piecewise Linear ◽  
Staggered Grid ◽  
Interface Tracking ◽  
Two Phase Flows ◽  
Time Step ◽  
Two Phase ◽  
Flow Equations ◽  
Fully Coupled

In this paper, we investigate the accuracy and robustness of three classes of methods for solving two-phase incompressible flows on a staggered grid. Here, the unsteady two-phase flow equations are simulated by finite volumes and penalty methods using implicit and monolithic approaches (such as the augmented Lagrangian and the fully coupled methods), where all velocity components and pressure variables are solved simultaneously (as opposed to segregated methods). The interface tracking is performed with a Volume-of-Fluid (VOF) method, using the Piecewise Linear Interface Construction (PLIC) technique. The home code Fugu is used for implementing the various methods. Our target application is the simulation of two-phase flows at high density and viscosity ratios, which are known to be challenging to simulate. The resulting strategies of monolithic approaches will be proven to be considerably better suited for these two-phase cases, they also allow to use larger time step than segregated methods.

scholarly journals Monolithic Solvers for Incompressible Two-Phase Flows at Large Density and Viscosity Ratios

2020 ◽  
Author(s):  
Mohamed EL OUAFA ◽  
stephane vincent ◽  
Vincent Le Chenadec
Keyword(s):  
Augmented Lagrangian ◽  
Incompressible Flows ◽  
Piecewise Linear ◽  
Staggered Grid ◽  
Interface Tracking ◽  
Two Phase Flows ◽  
Time Step ◽  
Two Phase ◽  
Flow Equations ◽  
Fully Coupled

In this paper, we investigate the accuracy and robustness of three classes of methods for solving two-phase incompressible flows on a staggered grid. Here, the unsteady two-phase flow equations are simulated by finite volumes and penalty methods using implicit and monolithic approaches (such as the augmented Lagrangian and the fully coupled methods), where all velocity components and pressure variables are solved simultaneously (as opposed to segregated methods). The interface tracking is performed with a Volume-of-Fluid (VOF) method, using the Piecewise Linear Interface Construction (PLIC) technique. The home code Fugu is used for implementing the various methods. Our target application is the simulation of two-phase flows at high density and viscosity ratios, which are known to be challenging to simulate. The resulting strategies of monolithic approaches will be proven to be considerably better suited for these two-phase cases, they also allow to use larger time step than segregated methods.

Application of Interface-Tracking Method Based on Phase-Field Model to Numerical Analysis of Isothermal and Thermal Two-Phase Flows

2007 ◽  
Author(s):  
Naoki Takada
Keyword(s):  
Phase Field ◽  
Density Ratio ◽  
Phase Field Model ◽  
Field Method ◽  
Diffuse Interface ◽  
Phase Field Method ◽  
Navier Stokes ◽  
Interface Tracking ◽  
Two Phase Flows ◽  
Two Phase

For interface-tracking simulation of two-phase flows in various micro-fluidics devices, the applicability of two versions of Navier-Stokes phase-field method (NS-PFM) was examined, combining NS equations for a continuous fluid with a diffuse-interface model based on the van der Waals-Cahn-Hilliard free-energy theory. Through the numerical simulations, the following major findings were obtained: (1) The first version of NS-PFM gives good predictions of interfacial shapes and motions in an incompressible, isothermal two-phase fluid with high density ratio on solid surface with heterogeneous wettability. (2) The second version successfully captures liquid-vapor motions with heat and mass transfer across interfaces in phase change of a non-ideal fluid around the critical point.

Using Graphics Processing Units to Accelerate Numerical Simulations of Interfacial Incompressible Flows

2012 ◽  
Author(s):  
Stephen R. Codyer ◽  
Mehdi Raessi ◽  
Gaurav Khanna
Keyword(s):  
Linear Algebra ◽  
Graphics Processing Units ◽  
Incompressible Flows ◽  
Stokes Equations ◽  
Surface Tension Force ◽  
Double Precision ◽  
Convergence Criteria ◽  
Time Step ◽  
Two Phase ◽  
Poisson Problem

We present a GPU accelerated numerical solver for incompressible, immiscible, two-phase fluid flows. This leads to a significant simulation speed-up and thus, the capability to have finer grid sizes and/or more accurate convergence criteria. We solve the Navier-Stokes equations, which include the surface tension force, by using a two-step projection method requiring the iterative solution to a pressure Poisson problem at each time step. However, running a serial linear algebra solver on a CPU to solve the pressure Poisson problem can take 50–99.9% of the total simulation time. To remove this bottleneck, we employ the large parallelization capabilities of GPUs by developing a double-precision parallel linear algebra solver, SCGPU, using NVIDIA’s CUDA v.4.0 libraries. The performance of SCGPU in serial simulations is presented, in addition to an evaluation of two pre-packaged GPU linear algebra solvers CUSP and CULA-sparse. We also present preliminary results of a GPU-accelerated MPI CPU flow solver.

scholarly journals Thermodynamically consistent modeling of two-phase incompressible flows in heterogeneous and fractured media

2020 ◽  
Vol 75 ◽  
pp. 32
Author(s):  
Huicai Gao ◽  
Jisheng Kou ◽  
Shuyu Sun ◽  
Xiuhua Wang
Keyword(s):  
Porous Media ◽  
Incompressible Flows ◽  
Classical Model ◽  
Fractured Media ◽  
Free Energy Function ◽  
Petroleum Reservoir ◽  
Two Phase Flows ◽  
Two Phase ◽  
Flows In Porous Media ◽  
Diffuse Interfaces

Numerical modeling of two-phase flows in heterogeneous and fractured media is of great interest in petroleum reservoir engineering. The classical model for two-phase flows in porous media is not completely thermodynamically consistent since the energy reconstructed from the capillary pressure does not involve the ideal fluid energy of both phases and attraction effect between two phases. On the other hand, the saturation may be discontinuous in heterogeneous and fractured media, and thus the saturation gradient may be not well defined. Consequently, the classical phase-field models can not be applied due to the use of diffuse interfaces. In this paper, we propose a new thermodynamically consistent energy-based model for two-phase flows in heterogeneous and fractured media, which is free of the gradient energy. Meanwhile, the model inherits the key features of the traditional models of two-phase flows in porous media, including relative permeability, volumetric phase velocity and capillarity effect. To characterize the capillarity effect, a logarithmic energy potential is proposed as the free energy function, which is more realistic than the commonly used double well potential. The model combines with the discrete fracture model to describe two-phase flows in fractured media. The popularly used implicit pressure explicit saturation method is used to simulate the model. Finally, the experimental verification of the model and numerical simulation results are provided.

scholarly journals Augmented Lagrangian and penalty methods for the simulation of two-phase flows interacting with moving solids. Application to hydroplaning flows interacting with real tire tread patterns

2011 ◽  
Vol 230 (4) ◽  
pp. 956-983 ◽  
Author(s):  
Stéphane Vincent ◽  
Arthur Sarthou ◽  
Jean-Paul Caltagirone ◽  
Fabien Sonilhac ◽  
Pierre Février ◽  
...  
Keyword(s):  
Augmented Lagrangian ◽  
Penalty Methods ◽  
Two Phase Flows ◽  
Two Phase

Calculation of Two-Phase Flows in an Oil Separator by Using a Cubic Interpolated Propagation Code on Unstructured Grid Spaces

2002 ◽  
Author(s):  
Eiji Ishii ◽  
Hirotaka Kameya ◽  
Atsushi Watanabe ◽  
Masayuki Urashin
Keyword(s):  
Finite Volume Method ◽  
Finite Volume ◽  
Unstructured Grid ◽  
Incompressible Flows ◽  
Critical Conditions ◽  
Two Phase Flows ◽  
Two Phase ◽  
Oil Separation ◽  
Liquid Flows ◽  
Volume Method

We have developed a cubic interpolated propagation (CIP) code combined with a finite volume method using unstructured grid spaces. The CIP code, which can solve both compressible and incompressible flows simultaneously, was used to calculate gas-liquid flows — in this case, waterspouts — in an oil separator. We found that waterspouts raise the oil at the bottom of the separator’s chamber and lower the efficiency of oil separation remarkably. We also found that the waterspouts can be classified as circulatory or non-circulatory and that they are caused by a low-pressure core in the discharge pipe. Furthermore, we predicted the critical conditions under which the waterspouts occur, and these predictions agree with measurements taken with a test separator.

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