scholarly journals A large scale interface multi-fluid model for simulating multiphase flows

2017 ◽  
Vol 44 ◽  
pp. 189-204 ◽  
Author(s):  
Vinesh H. Gada ◽  
Mohit P. Tandon ◽  
Jebin Elias ◽  
Roman Vikulov ◽  
Simon Lo
Keyword(s):  
Multiphase Flows ◽  
Large Scale ◽  
Fluid Model

Sand Erosion in Multiphase Flow for Low-Liquid Loading and Annular Conditions

2012 ◽  
Author(s):  
R. E. Vieira ◽  
N. R. Kesana ◽  
B. S. McLaury ◽  
S. A. Shirazi
Keyword(s):  
Multiphase Flow ◽  
Multiphase Flows ◽  
Large Scale ◽  
Flow Patterns ◽  
Production Equipment ◽  
Flow Loop ◽  
Liquid Loading ◽  
Vertical Orientation ◽  
Horizontal Orientation ◽  
Sand Erosion

Low-liquid loading (LLL) and annular gas-liquid flow patterns are commonly encountered in gas transportation pipelines. They may also occur in other off-shore production facilities such as gas/condensate production systems. Experience gained from production of hydrocarbons has shown that severe degradation of production equipment will occur due to sand entrained in gas-dominant multiphase flows. Sand erosion in multiphase flows is a complex phenomenon since several factors influence the particle impact velocity with the wall. In order to give a more comprehensive understanding of the particle erosion process in this particular scenario and to improve the current semi-mechanistic models, erosion and sand distribution measurements were conducted on 76.2 mm (3 inch) and 101.6 mm (4 inch) diameter pipes in a large scale multiphase flow loop with varying gas (air) and liquid (water) velocities generating low-liquid loading and annular conditions. Particle sizes used in the experiments were 150 and 300 microns with the latter being sharper than the former. Erosion measurements were made at sixteen different locations on a 76.2 mm (3 inch) standard elbow using ultrasonic technology, whereas Electrical Resistance (ER) probes were used for the measurements in a 101.6 mm (4 inch) diameter pipe. The experiments were primarily performed in the upward vertical orientation but a few measurements were performed in the horizontal orientation. Results suggest that the erosion is an order of magnitude higher when the pipe is oriented vertically compared to horizontal orientation. Also, the location of maximum erosion is identified for these flow patterns and it is not dependent on the pipe inclination.

Computational Fluid-Structure Interaction of DGB Parachutes in Compressible Fluid Flow

2010 ◽  
Author(s):  
Carlos Pantano-Rubino ◽  
Kostas Karagiozis ◽  
Ramji Kamakoti ◽  
Fehmi Cirak
Keyword(s):  
Adaptive Mesh Refinement ◽  
Compressible Flows ◽  
Large Scale ◽  
Structural Model ◽  
Fluid Model ◽  
Fluid Structure Interaction ◽  
Adaptive Mesh ◽  
Turbulent Wake ◽  
Fluid Structure ◽  
Structure Interaction

This paper describes large-scale simulations of compressible flows over a supersonic disk-gap-band parachute system. An adaptive mesh refinement method is used to resolve the coupled fluid-structure model. The fluid model employs large-eddy simulation to describe the turbulent wakes appearing upstream and downstream of the parachute canopy and the structural model employed a thin-shell finite element solver that allows large canopy deformations by using subdivision finite elements. The fluid-structure interaction is described by a variant of the Ghost-Fluid method. The simulation was carried out at Mach number 1.96 where strong nonlinear coupling between the system of bow shocks, turbulent wake and canopy is observed. It was found that the canopy oscillations were characterized by a breathing type motion due to the strong interaction of the turbulent wake and bow shock upstream of the flexible canopy.

scholarly journals Landau fluid closures with nonlinear large-scale finite Larmor radius corrections for collisionless plasmas

2014 ◽  
Vol 81 (1) ◽  
Author(s):  
P. L. Sulem ◽  
T. Passot
Keyword(s):  
Large Scale ◽  
Fluid Model ◽  
Low Frequency ◽  
Larmor Radius ◽  
Large Temperature ◽  
Ion Cyclotron Resonance ◽  
Finite Larmor Radius ◽  
Collisionless Plasmas ◽  
Kinetic Effects ◽  
Linear Kinetic Theory

With the aim to develop a tool for simulating turbulence in collisionless magnetized plasmas, fluid models retaining low-frequency kinetic effects such as Landau damping and finite Larmor radius (FLR) corrections are discussed. It turns out that, in the absence of ion-cyclotron resonance, the dispersion and damping of kinetic Alfvén waves at scales as small as a fraction of the ion Larmor radius are accurately reproduced when using fluid estimates of the non-gyrotropic moments, at leading-order within a large-scale asymptotics. Differently, evaluations based on the low-frequency linear kinetic theory are necessary in regimes of large temperature anisotropies, and in particular in the presence of the mirror instability. Combining both descriptions leads to a new Landau fluid model retaining large-scale FLR nonlinearities, while reproducing the linear dynamics of low-frequency modes at the sub-ionic scales.

scholarly journals A multi-fluid model of the magnetopause

2019 ◽  
Author(s):  
Roberto Manuzzo ◽  
Francesco Califano ◽  
Gerard Belmont ◽  
Laurence Rezeau
Keyword(s):  
Solar Wind ◽  
Electromagnetic Fields ◽  
Large Scale ◽  
Fluid Model ◽  
Analytic Model ◽  
Equilibrium Equations ◽  
Magnetic Field Topology ◽  
Initial Equilibrium State ◽  
Magnetospheric Multiscale Mission ◽  
The Stability

Abstract. Observation of the solar wind – magnetosphere boundary provides a unique opportunity to investigate the physics underlying the interaction between two collisionless magnetized plasmas with different temperature, density and magnetic field topology. Their mixing across the interface as well as the boundary dynamics are affected by the development of fluid (and kinetic) instabilities driven by large scale inhomogeneities in particle and electromagnetic fields. Building up a realistic initial equilibrium state of the magnetopause according to observations is still a challenge nowadays. In this paper we address the modeling of the particles and electromagnetic fields configuration across the Earth's magnetopause by means of a three-fluid analytic model. The model relies on one hot and one cold ion population and on a neutralizing electron population. The goal is to build up an analytic model able to reproduce as closely as possible the observations. Some parameters of the model are set by using a fit procedure aiming at minimizing their difference with respect to experimental data provided by the Magnetospheric MultiScale mission. All the other profiles, concerning the electron pressure and the relative densities of the cold and hot ion populations, are calculated in order to satisfy the fluid equilibrium equations. Finally, by means of a new tri-fluid code, we have checked the stability of the large-scale equilibrium model for a given experimental case and given the proof that the system is unstable to reconnection. This model could be of interest for the interpretation of satellite results and for the study of the dynamics at the boundary between the Magnetosphere and the solar wind.

A Hybrid Method for Simulating Flows Including Fluid Particles

2006 ◽  
Author(s):  
Akiyoshi Maeda ◽  
Akira Sou ◽  
Akio Tomiyama
Keyword(s):  
Particle Tracking ◽  
Hybrid Method ◽  
Large Scale ◽  
Fluid Model ◽  
Bubbly Flow ◽  
Particle Diameter ◽  
Interface Tracking ◽  
Wide Range ◽  
Standard Interface ◽  
Dynamics Method

A hybrid CMFD (computational multi-fluid dynamics) method is proposed for the prediction of multiphase flows including large-scale interface, poly-dispersed bubbles and/or drops. The method is the hybrid integration of an interface tracking method (ITM), three kinds of particle tracking methods (PTM) and an averaging method based on a multi-fluid model (MFM). The integration enables us (1) to cover a wide range of d* = d/Δx, where d is the particle diameter and Δx the grid size, and (2) to perform various kinds of multiphase CFD such as standard interface tracking, particle tracking and multi-fluid simulations, and hybrid simulations using an arbitrary combination of ITM, PTM and MFM. The field and constitutive equations of the proposed method are described in detail. A poly-dispersed air-water bubbly flow and several bubble plumes in a small open vessel are simulated using the proposed hybrid method to demonstrate its potential.

scholarly journals Beyond single-stream with the Schrödinger method

2014 ◽  
Vol 11 (S308) ◽  
pp. 115-118
Author(s):  
Cora Uhlemann ◽  
Michael Kopp
Keyword(s):  
Dark Matter ◽  
Phase Space ◽  
Poisson Equation ◽  
Large Scale ◽  
Fluid Model ◽  
Numerical Technique ◽  
Analytical Tool ◽  
The Common ◽  
Large Scale Structure Formation ◽  
Space Description

AbstractWe investigate large scale structure formation of collisionless dark matter in the phase space description based on the Vlasov-Poisson equation. We present the Schrödinger method, originally proposed by \cite{WK93} as numerical technique based on the Schrödinger Poisson equation, as an analytical tool which is superior to the common standard pressureless fluid model. Whereas the dust model fails and develops singularities at shell crossing the Schrödinger method encompasses multi-streaming and even virialization.

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