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Implementation of piso algorithm for simulating unsteady cavitating flows

OCEAN ENGINEERING 2010年第14-15期37卷 1321-1336页

作者： Seif, M. S. Asnaghi, A. Jahanbakhsh, E. Sharif Univ Technol Tehran Iran

The present study focuses on the implementation of piso algorithm to simulate cavitating flows. For simulation of unsteady behaviors of cavitation which have practical applications, the development of unsteady piso algorithm based on the non-conservative approach is investigated. The effects of mixture compressibility are considered to improve accuracy of simulations. For multi-phase simulation, single-fluid Navier-Stokes equations, along with the volume fraction transport equation, are employed. The bubble dynamics model is utilized to simulate phase change. To prove capabilities of the developed piso algorithm to simulate cavitating flows, unsteady simulation of cavitation around NACA0015 hydrofoil, a two dimensional flat plat, and a three dimensional circular disk are performed. The frequency of flow, pressure distributions, cavitating vortex shedding, and cavity characteristics are analyzed to discern results accuracy. To investigate accuracy of results, comparisons with available published experimental data are made and good agreement is achieved. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Numerical simulation Cavitation piso algorithm Non-conservative approach Unsteady flow

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A piso-like algorithm to simulate superfluid helium flow with the two-fluid model

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COMPUTER PHYSICS COMMUNICATIONS 2015年 187卷 20-28页

作者： Soulaine, Cyprien Quintard, Michel Allain, Herve Baudouy, Bertrand Van Weelderen, Rob Univ Toulouse INPT UPS IMFT F-31400 Toulouse France CNRS IMFT F-31400 Toulouse France CERN TE CRG CH-1211 Geneva 23 Switzerland CEA Saclay Irfu SACM F-91191 Gif Sur Yvette France

This paper presents a segregated algorithm to solve numerically the superfluid helium (He II) equations using the two-fluid model. In order to validate the resulting code and illustrate its potential, different simulations have been performed. First, the flow through a capillary filled with Hell with a heated area on one side is simulated and results are compared to analytical solutions in both Landau and Gorter-Mellink flow regimes. Then, transient heat transfer of a forced flow of He Ills investigated. Finally, some two-dimensional simulations in a porous medium model are carried out. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Cryogenic Two-fluid model Superfluid helium Simulation piso algorithm

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Numerical simulation of the movement of the water surface with macroscopic particles during a partial dam break for various complex reliefs

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SIMULATION-TRANSACTIONS OF THE SOCIETY FOR MODELING AND SIMULATION INTERNATIONAL 2025年第1期101卷 13-28页

作者： Issakhov, Alibek Abylkassymova, Aizhan Minnullina, Saniya Kazakh British Tech Univ Alma Ata 050000 Kazakhstan Al Farabi kazakh Natl Univ Almatyt Kazakhstan Int Informat Technol Univ Alma Ata Kazakhstan

In this paper, it was considered a numerical simulation of the water surface movement during the partial collapse of the destruction of a dam with complex terrain. The numerical simulations took into account debris after a partial collapse of the dam, which imitates debris and moves downstream with the water flow. Carrying out these calculations brings the results closer to the real scenario. The mathematical model was based on the Navier-Stokes equations and uses the turbulent large eddy method (LES) model describing the flow of an incompressible viscous fluid. To describe the movement of a two-phase fluid, the volume of fluid (VOF) methods for the phase were used, and the Discrete Phase Model (DPM) and Macroscopic Particle Model (MPM) were used to describe the movement of particles. For the numerical solution of this system of equations, the Pressure Implicit Split Operator (piso) numerical algorithm was chosen. The results show that the model is accurate and capable of handling very complex interactions such as particle transport or hydrodynamic actions on structures if the appropriate scales are reproduced. Also in this work, a three-dimensional (3D) model of the flow of a dam break on uneven terrain was considered and combined problems were performed that are closer to real conditions. For combined problems, flood zones and flood times were determined, knowledge of which will help evacuate people from dangerous areas. The accuracy of the 3D model and the selected numerical algorithm were verified using two natural measurements.

关键词： Dam break modeling MPM and DPM interaction of macroscopic particles flood zones piso algorithm VOF method

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Comparison of SIMPLE- and piso-type algorithms for transient flows

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS 1998年第4期26卷 459-483页

作者： Barton, IE Univ Cambridge Dept Engn Div A CFD Lab Cambridge CB2 1PZ England

Various pressure-based schemes are proposed for transient flows based on well-established SIMPLE and piso algorithms. The schemes are applied to the solution of unsteady laminar how around a square cylinder and steady laminar flow over a backward-facing step. The implicit treatment and the performance of the various schemes are evaluated by using benchmark solutions with a small time step. Three different second-order-accurate time derivatives based on different time levels are presented. The different time derivatives are applied to the various schemes under consideration. Overall the piso scheme was found to predict accurate results and was robust. However, for small time step values, alternative schemes can predict accurate results for approximately half the computational cost. The choice of time derivative proved to be very significant in terms of the accuracy and robustness of a scheme. Significantly, the one-sided forward differencing scheme was the most successful used in conjunction with a strongly implicit-based algorithm. However, a greater degree of accuracy was achieved using the standard piso algorithm with the Crank-Nicolson time derivative. Recommendations for future work are discussed. (C) 1998 John Wiley & Sons, Ltd.

关键词： SIMPLE algorithm piso algorithm unsteady incompressible flow

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Development of a piso-SPH method for computing incompressible flows

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE 2014年第3期228卷 481-490页

作者： Tayebi, Ali Dehkordi, Behzad Ghadiri Tarbiat Modares Univ Dept Mech Engn Teran Iran

A new algorithm is proposed for solving the time-dependent Navier-Stokes equations in a sequential uncoupled manner. The algorithm, known as piso (Pressure Implicit with Splitting of Operators) is extended to the Smoothed Particle Hydrodynamics (SPH) context (piso-SPH). The algorithm consists of one prediction and two correction steps, based on a full Navier-Stokes equation, therefore, a modified Poisson equation is derived which makes the algorithm more stable with less pressure fluctuations. The proposed piso-SPH method is applied to solve a number of benchmark problems including both unsteady and steady state test cases. Comparing the results with analytical solutions and other numerical methods, it is shown that the proposed method is accurate and straightforward for the simulation of incompressible fluid flows.

关键词： SPH piso algorithm prediction-correction Poisson equation

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THE RESEARCH ON HIGH-SPEED GAS JET OF ROCKET NOZZLE UNDERWATER

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Journal of Hydrodynamics 2005年第2期17卷 204-208页

作者： XUXiao-qiang DENGJian RENAn-lu LUChuan-jing DepartmentofMechanics ZhejiangUniversityHangzhou310027China SchoolofNavalArchitecture OceanandCivilEngeneering~ShanghaiJiaotongUniversityShanghai200030China

In this paper, a study of the high-speed gas jet of a rocket nozzle underwater was carried out using commercially available CFD software FLUENT with it’s user-defined-function. The volume of fluid technique based on finite volume method was adopted to solve the time-dependent multiphase flow including a compressible phase, and the piso algorithm was included. The computed results show that this problem was calculated successfully. The gas bubble behind the nozzle, and the wave structure existing in highly compressed gas in water were captured accurately.

关键词： rocket nozzle underwater piso algorithm wave structure bubble structure user-defined-function

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Numerical simulation of the movement of water surface of dam break flow by VOF methods for various obstacles

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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2019年 136卷 1030-1051页

作者： Issakhov, Alibek Imanberdiyeva, Medina Al Farabi Kazakh Natl Univ Av Al Farabi 71 Alma Ata 050040 Kazakhstan

In this paper, the movement of the water surface is numerically simulated when a dam is broken by the volume of fluid (VOF) method. The mathematical model is based on the Navier-Stokes equations and uses the LES turbulent model, describing the flow of an incompressible viscous fluid and the equation for the phase. These equations are discretized by the finite volume method. Numerical piso algorithm was chosen for numerical solution of this equation system. The movement of the water surface is captured by using the VOF method, which leads to a strict mass conservation law. The accuracy of the 3D model and the chosen numerical algorithm were tested using several laboratory experiments on dam break problem. In each of the problems, the obtained results were compared with the experimental data and several calculations by other authors and in each of the test problems, the developed model showed results close to the experimental data. Comparison of simulation results with experimental data for various turbulent models was also performed. And also a three-dimensional model of dam break flow on uneven terrain was developed. And also two combined problems were performed which are more close to real conditions, with the help of these problems, flooding zones and flooding time were identified that would help in evacuating people from dangerous zones. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Dam breaks modeling Flood zone Navier-Stokes equations piso algorithm VOF method Large eddy simulation (LES)

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Numerical Simulation of Dam Break Waves on Movable Beds for Various Forms of the Obstacle by VOF Method

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WATER RESOURCES MANAGEMENT 2020年第8期34卷 2269-2289页

作者： Issakhov, Alibek Zhandaulet, Yeldos Al Farabi Kazakh Natl Univ Alma Ata Kazakhstan Kazakh British Tech Univ Alma Ata Kazakhstan

This paper considered the problem of numerical simulation of an incompressible dam break flow consisting of three phases. The movement of the water free surface was carried out using the Newtonian fluid model, and the mud impurity movement was performed by the non-Newtonian fluid model based on the VOF method. The piso numerical algorithm was chosen as a numerical method for solving equations. This paper discusses the problems of dynamic loads arising from the impact of a dam break flow using numerical modeling. The obtained numerical results were compared with the two experiment results, which allow confirming the behavior of the instantaneous flow and the evolution of pressure at the relative points of the obstacle. Moreover the water flow and non-Newtonian fluid for different forms of obstacles were also modeled. It was found that a non-Newtonian fluid extremely reduces the maximum shock pressure value of the water flow.

关键词： Dam break flow modeling Mud flow Non-Newtonian fluid piso algorithm VOF method

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Numerical study of dam break waves on movable beds for various forms of the obstacle by VOF method

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OCEAN ENGINEERING 2020年 209卷 107459-107459页

作者： Issakhov, Alibek Zhandaulet, Yeldos Al Farabi Kazakh Natl Univ Alma Ata Kazakhstan Kazakh British Tech Univ Alma Ata Kazakhstan

This paper considered the problem of numerical simulation of an incompressible dam break flow consisting of three phases. The movement of the water free surface is performed using the Newtonian fluid model, and the mud mixture movement is carried out by the non-Newtonian fluid model based on the VOF method. The piso numerical algorithm was selected as a numerical method for solving equations. This paper discusses the problems of dynamic loads arising from the impact of a dam break flow using numerical modeling. The received computational data are matched with the two experiment results, which allow confirming the behavior of the instantaneous flow and the evolution of pressure at the relative points of the obstacle. The water flow and non-Newtonian fluid for different forms of obstacles were also modeled. It was found that a non-Newtonian fluid rather strongly reduces the maximum shock the pressure value of the water flow.

关键词： Mud flow Dam break flow modeling Non-Newtonian fluid VOF method piso algorithm

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Parallel numerical simulation for the coupled problem of continuous flow electrophoresis

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS 2007年第10期55卷 945-963页

作者： Chau, M. Spiteri, P. Boisson, H. C. ENSEEIHT IRIT F-31071 Toulouse France IMFT F-31400 Toulouse France

The performance of parallel subdomain method with overlapping is analysed in the case of the 3D coupled boundary-value problem of continuous flow electrophoresis which is governed by Navier-Stokes equations coupled with convection-diffusion and potential equations. Convergence of parallel synchronous and asynchronous iterative algorithms is studied. Comparison between implemented explicit and implicit schemes for the transport equation is made using these algorithms and shows that both methods provide similar results and comparable performances. Copyright (C) 2007 John Wiley & Sons, Ltd.

关键词： parallel computing continuous-flow electrophoresis Schwarz alternating method asynchronous iterations piso algorithm mass transfer

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