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Showing papers on "Volume of fluid method published in 1999"


Journal ArticleDOI
TL;DR: In this article, a volume-of-fluid interface tracking technique that uses a piecewise-linear interface calculation in each cell is described, and the momentum balance is computed using explicit finite volume/finite differences on a regular cubic grid.

947 citations


Journal ArticleDOI
TL;DR: In this article, the impact of a single drop on a liquid film is studied numerically by solving the Navier-Stokes equations for incompressible fluids in three dimensions, and the extension dynamics of the splashing lamella is analyzed and compared with theoretical results from the literature.

224 citations


Patent
14 Jul 1999
TL;DR: In this article, a fluid or gas delivery system consisting of single or double control valves for regulating flow of a first fluid and a second fluid from corresponding first and second fluid sources into a mixing port is provided.
Abstract: A fluid or gas delivery system is provided for controlling fluid or gas temperature, flow rate and volume at a system outlet. The system comprises single or double control valves for regulating flow of a first fluid or gas and a second fluid or gas from corresponding first and second fluid or gas sources into a mixing port, wherein the first fluid or gas has a different temperature from the second fluid or gas. A fluid or gas supply control valve actuator operatively connected to the first and second fluid or gas supply valves actuate opening and closure operations of the valves. A thermosensor thermally coupled with the mixing port senses an estimated present temperature of a mixed fluid or gas within the mixing port. A flow control valve regulates flow of a mixed fluid or gas at the system outlet. A flow control valve actuator operatively connected to the flow control valve actuates opening and closure thereof. A user interface including user input means for selecting a set temperature, flow rate and volume of fluid or gas at the system outlet is provided along with a user display for displaying one or more system functions or parameters. Control means are provided for receiving signals from the thermosensor and user interface and for processing the signals to generate appropriate control signals to control the fluid or gas supply control valve actuator and flow control valve actuator means to achieve programmed or user-selected set temperature, flow rate and volume at the system outlet.

210 citations


Journal ArticleDOI
TL;DR: In this paper, numerical simulations of plunging breakers including the splash-up phenomenon are presented, where the motion is governed by the classical, incompressible, two-dimensional Navier-Stokes equation.
Abstract: Numerical simulations describing plunging breakers including the splash-up phenomenon are presented. The motion is governed by the classical, incompressible, two-dimensional Navier–Stokes equation. The numerical modeling of this two-phase flow is based on a piecewise linear version of the volume of fluid method. Capillary effects are taken into account such as a nonisotropic stress tensor concentrated near the interface. Results concerning the time evolution of liquid–gas interface and velocity field are given for short waves, showing how an initial steep wave undergoes breaking and successive splash-up cycles. Breaking processes including overturning, splash-up and gas entrainment, and breaking induced vortex-like motion beneath the surface and energy dissipation, are presented and discussed. It is found that strong vorticities are generated during the breaking process, and that more than 80% of the total pre-breaking wave energy is dissipated within three wave periods. The numerical results are compared with some laboratory measurements, and a favorable agreement is found.

200 citations


Journal ArticleDOI
TL;DR: In this article, the rise and deformation of a gas bubble in an otherwise stationary liquid contained in a closed, right vertical cylinder is investigated using a modified volume-of-fluid (VOF) method incorporating surface tension stresses.
Abstract: The rise and deformation of a gas bubble in an otherwise stationary liquid contained in a closed, right vertical cylinder is investigated using a modified volume-of-fluid (VOF) method incorporating surface tension stresses. Starting from a perfectly spherical bubble which is initially at rest, the upward motion of the bubble in a gravitational field is studied by tracking the liquid–gas interface. The gas in the bubble can be treated as incompressible. The problem is simulated using primitive variables in a control-volume formulation in conjunction with a pressure–velocity coupling based on the SIMPLE algorithm. The modified VOF method used in this study is able to identify and physically treat features such as bubble deformation, cusp formation, breakup and joining. Results in a two-dimensional as well as a three-dimensional coordinate framework are presented. The bubble deformation and its motion are characterized by the Reynolds number, the Bond number, the density ratio, and the viscosity ratio. The effects of these parameters on the bubble rise are demonstrated. Physical mechanisms are discussed for the computational results obtained, especially the formation of a toroidal bubble. The results agree with experiments reported in the literature.

174 citations


Journal ArticleDOI
TL;DR: In this article, a new approach that can predict the characteristics of discrete phases of three-phase flows is provided, which combines a combined method of the computational fluid dynamics (CFD) with the discrete particle method (DPM) and a volume-tracking represented by the volume-of-fluid (VOF) method.

155 citations


Journal ArticleDOI
TL;DR: In this article, the authors present numerical results of the dynamics of a viscous liquid drop that is being formed directly at the tip of a vertical, circular tube and breaks into an ambient, viscous fluid.

99 citations


Journal ArticleDOI
TL;DR: In this paper, the authors attempted to simulate the rise trajectories of gas bubbles of 4, 5, 7, 8, 9, 12, and 20 mm in diameter rising in a 2D rectangular column filled with water.

78 citations


Journal ArticleDOI
TL;DR: In this paper, a numerical model for the simulation of complex fluid flows with free surfaces is presented, where the unknowns are the velocity and pressure fields in the liquid region, together with a function defining the volume fraction of liquid.

74 citations


Journal ArticleDOI
18 Mar 1999-Nature
TL;DR: In this paper, the authors simulate the motion of single gas bubbles in a liquid using the volume-of-fluid (VOF) technique, which allows them to describe the complex bubble dynamics using only the fluid phase properties as inputs.
Abstract: Understanding the motion of gas bubbles in a liquid is a problem of both scientific and engineering importance. About 500 years ago, Leonardo da Vinci1 summarized his observations on the motion of air bubbles in a liquid: “The air that submerged itself with the water returns to the air, penetrating the water in sinuous movement, changing its substance into a great number of forms it never spreads itself out from its path except to the extent to which it avoids the water which covers it”. We have attempted to simulate the motion of single gas bubbles in a liquid using the volume-of-fluid (VOF) technique, which allows us to describe the complex bubble dynamics using only the fluid phase properties as inputs.

70 citations


Journal ArticleDOI
TL;DR: In this article, an active wave generating-absorbing boundary condition for a numerical model based on the Volume Of Fluid (VOF) method for tracking free surfaces is discussed, and the practical use of this numerical boundary condition is compared to the use of the absorption system in a physical wave flume.

Journal ArticleDOI
TL;DR: In this article, a mathematical model is developed to describe the heat transfer and fluid flow in stationary keyhole plasma arc welding, and the processes of heating, melting, collapsing and subsequent solidifying in the molten pool are dynamically studied.
Abstract: A mathematical model is developed to describe the heat transfer and fluid flow in stationary keyhole plasma arc welding. Using the volume of fluid method, the processes of heating, melting, collapsing and subsequent solidifying in the molten pool are dynamically studied. The predicted results have been compared with the experimental weld and keyhole shape. Using the LaserStrobe video system, the captured images of the upper surface of the weld pool are used to verify the predicted transient development of the weld pool. It is indicated that theoretical predictions and the experimental results are in close agreement.

Journal ArticleDOI
Koji Kawasaki1
TL;DR: A numerical wave model for two-dimensional wave field in the vertical plane is proposed in this article, which combines a VOF method with a non-reflective wave generator in addition to the open-bounded wave generator.
Abstract: A numerical wave model for two-dimensional wave field in the vertical plane is proposed in this study. The model combines a VOF method with a non-reflective wave generator in addition to the open b...

30 May 1999
TL;DR: In this article, a wave tank based on the coupling of a Boundary Element model, solving fully nonlinear potential flow equations, and a volume of fluid model solving Navier-Stokes equations is developed and used to calculate transformation of shoaling and breaking waves in nearshore areas.
Abstract: A numerical wave tank based on the coupling of a Boundary Element model, solving fully nonlinear potential flow equations, and a Volume Of Fluid model solving Navier-Stokes equations is developed and used to calculate transformation of shoaling and breaking waves in nearshore areas.

Journal ArticleDOI
TL;DR: In this paper, a three-dimensional quasi-steady welding is simulated by an unsteady two-dimensional process, and the transport process on the maximum cross section of the molten region (or a cross-section of the fusion zone) is predicted.
Abstract: Velocity and temperature fields, and shapes of the fusion zone in welding dissimilar metals are systematically investigated. Fluid flow in the molten pool is driven by the Marangoni force in different directions and magnitudes on the flat free surface. To interpret clearly without loss of generality, the three-dimensional quasi-steady welding is simulated by an unsteady two-dimensional process. Transport process on the maximum cross section of the molten region (or a cross section of the fusion zone) therefore is predicted. Interfaces between immiscible dissimilar metals and solid and liquid are, respectively, calculated by the volume of fluid and enthalpy methods

Journal ArticleDOI
TL;DR: In this article, the authors present numerical computations for the analysis of Dam-Break Flow using two-dimensional flow equations in a vertical plane, using the general approach of the simplified marker and cell method combined with the volume of fluid approach for the surface tracking.
Abstract: This work presents numerical computations for the analysis of Dam-Break Flow using two-dimensional flow equations in a vertical plane. The numerical model uses the general approach of the simplified marker and cell method combined with the volume of fluid approach for the surface tracking. The time evolution of flow depth at the dam site and the evolution of the pressure distribution are investigated for both wet and dry bed conditions. The effect of the initially nonhydrostatic state on the long term surface profile and wave velocity are studied. These long term effects are found to be marginal in the case of wet-bed conditions, but are significant in dry-bed conditions. The dry-bed tip velocity immediately after the dam break, computed numerically, compares well with analytical results published previously. The time taken to obtain a constant flow depth at the dam site increases with decreasing initial depth ratio. The numerical result for this time elapse for dry-bed conditions is close to the experime...

Patent
21 Sep 1999
TL;DR: A solids separation system may be used to separate solids, such as cuttings from drilling fluids used in well drilling operations as mentioned in this paper, using a settling tank having transverse baffles defining a fluid receiving chamber, a fluid output chamber and one or more intermediate chambers.
Abstract: A solids separation system may be used to separate solids, such as cuttings from drilling fluids used in well drilling operations. The system includes a settling tank having transverse baffles defining a fluid receiving chamber, a fluid output chamber and one or more intermediate chambers. Fluid introduced into the fluid receiving chamber can flow in a sinuous path through apertures in the baffles to the fluid output chamber. Solids settle to the bottom of the settling tank. A material conveyor, preferably an auger, extends along a bottom surface of the settling tank to an outlet port in the fluid receiving chamber. A centrifuge is connected to the output port to receive fluid in which solids have been concentrated. Fluid output from the centrifuge is reintroduced into the settling tank. The apparatus and method of the invention permit a single centrifuge to be used to handle a higher volume of fluid than is possible with conventional methods and apparatus. This provides significant cost savings.

DOI
26 Apr 1999
TL;DR: In this paper, the VOF method for free surface flow is applied to simulate breaking waves incident on a submerged reef and an efficient numerical wave channel with two absorbing boundaries is developed.
Abstract: In this paper, the VOF method for free surface flow is applied to simulate breaking waves incident on a submerged reef. An efficient numerical wave channel with two absorbing boundaries is developed. Corresponding boundary conditions are prescribed. Smagorinsky's sub-grid scale model is incorporated to account for the sub-grid scale turbulence. Numerical results are compared with laboratory measurements.

01 Jan 1999
TL;DR: This research attacked the mode confusion problem by developing a modeling framework called “Smart Source Parsing” to describe the “building blocks” of human interaction with mode-based systems.
Abstract: Note: Using Smart Source Parsing 18-23 3 Reference LMH-CONF-1999-005 Record created on 2005-11-04, modified on 2017-05-10

Journal ArticleDOI
TL;DR: In this paper, a model with density currents has been developed and tested to simulate bed load sediment traps, where the bed load layer over the pipe invert is considered as a continuous layer characterised by a density and a viscosity which depends on the solid concentration.

Journal ArticleDOI
TL;DR: In this article, a multidirectional solidification algorithm is adapted and implemented in the Navier-Stokes solver to perform numerical simulations of liquid-metal droplet impact, spreading and solidification, and results obtained allow a detailed description of the liquid-jet overflow mechanism and of the resulting solidified disk morphology.

Journal Article
TL;DR: In this article, simple modifications for higher-order Godunov type difference schemes are presented which allow for accu- rate advection of multi-fluid flows in hydrodynamic simulations.
Abstract: Simple modifications for higher-order Godunov- type difference schemes are presented which allow for accu- rate advection of multi-fluid flows in hydrodynamic simulations. The constraint that the sum of all mass fractions has to be equal to one in every computational zone throughout the simulation is fulfilled by renormalizing the mass fractions during the ad- vection step. The proposed modification is appropriate for any difference scheme written in conservation form. Unlike other commonly used methods it does not violate the conservative character of the advection method. A new steepening mecha- nism, which is based on modification of interpolation profiles, is used to reduce numerical diffusion across composition discon- tinuities. Additional procedures are described, which are nec- essary to enforce monotonicity. Several numerical experiments are presented which demonstrate the capability of our Consis- tent Multi-fluid Advection (CMA) method in case of smooth and discontinuous distributions of fluid phases and under different hydrodynamic conditions. It is shown that due to the reduced diffusivity of the proposed scheme the abundance of some heavy elements obtained from hydrodynamic simulations of type II su- pernova explosions can change by a factor of a few in the most extreme cases.

Journal ArticleDOI
TL;DR: In this paper, a new method for the retrieval of 3D wind fields at mesoscale and convective scale from dual-beam airborne Doppler radar data corrected for a time-induced advection problem is presented.
Abstract: The present paper is devoted to a new method for the retrieval of three-dimensional wind fields at mesoscale and convective scale from dual-beam airborne Doppler radar data corrected for a time-induced advection problem. Data are obtained from airborne or/and ground-based Doppler radar. This correction is based on a new formalism for the determination of the advection speed. This formalism is mathematically described in this paper and an application to simulated and real wind fields deduced from the Multiple Analytical Doppler (MANDOP) method is presented. Thus, it benefits from the analytical formulation used in the MANDOP analysis. The resulting procedure called MANDOPA allows one to retrieve the 3D wind field corrected for the time-induced advection problem without the input of an advection speed retrieved independently. The procedure also allows one to retrieve the advection speed. This method is based on a minimization process between the theoretical temporal evolution of the radial velocity...

Journal ArticleDOI
TL;DR: In this paper, a constitutive model for the collision process between two fluid particles is proposed, which can be applied for determining whether the particles will coalesce or not, and is applicable for both phenomenological and CFD-based reactor models.

Journal ArticleDOI
TL;DR: In this article, a numerical analysis has been performed on the rapid solidification in a single roller cooling process using the volume of fluid (VOF) method, which was adopted as the numerical method used to simulate transient two-dimensional thermal and fluid flow with a liquid-solid phase change and free surfaces.
Abstract: The rapid solidification in a single roller process has been used to make amorphous ribbons. Because this process occurs rapidly, it is difficult to obtain useful experimental data. Therefore, a numerical analysis has been performed on the rapid solidification in a single roller cooling process. The VOF (volume of fluid) method was adopted as the numerical method used to simulate transient two-dimensional thermal and fluid flow with a liquid-solid phase change and free surfaces. We simulated the behavior of an aluminum alloy. The geometry of the amorphous ribbon, flow and temperature fields, temperature history of alloy particle whose initial location is at the center of the nozzle, and the cooling rate were obtained using as parameters the roll velocity, the nozzle slot breadth, and the gap between nozzle and roller.

Journal ArticleDOI
TL;DR: In this paper, a modified method of characteristics is developed for incompressible Darcy flow, where the elements are modeled as grid cells and a strict equality of volumes is imposed between the two.

Journal Article
TL;DR: In this paper, the volume of fluid (VOF) method is used to set up a wave flume with an absorbing wave maker of cnoidal waves, based on the transfer function between wave surface and paddle velocity obtained by the shallow water wave theory.
Abstract: The volume of fluid (VOF) method is used to set up a wave flume with an absorbing wave maker of cnoidal waves. Based on the transfer function between wave surface and paddle velocity obtained by the shallow water wave theory, the velocity boundary condition of an absorbing wave maker is introduced to absorb reflected waves that reach the numerical wave maker. For H/d ranging from 0.1 to 0.59 and T g/d from 7.9 to 18.3, the parametric studies have been carried out and compared with experiments.

Journal ArticleDOI
TL;DR: The magnetic field at the surface of the Sun is confined to widely separated small, intense magnetic flux bundles or fibrils with most of the gas in a relatively field free state in the interstices as discussed by the authors.
Abstract: The magnetic field at the surface of the Sun is confined to widely separated small, intense magnetic flux bundles or fibrils with most of the gas in a relatively field free state in the interstices. There is evidently a systematic field and fluid separation effect in operation, overriding the tendency for turbulent mixing of the two phases. It is well known that a constantly rotating volume of fluid soon excludes any exterior magnetic field. To take the next theoretical step, this paper examines the exclusion of magnetic field from a circular cylinder with oscillating angular velocity. The result is that the field is effectively excluded from any oscillating or tumbling body of fluid that maintains coherence over a sufficiently long time. However, there is no expectation of such long term coherence in turbulent convection in the Sun, suggesting that the observed separation of field and fluid does not come about by the exclusion of field from convective cells. This leads to the conclusion that the separation of fluid and field is a consequence of extraction of fluid from the field through buoyancy and reconnection.

Journal ArticleDOI
TL;DR: In this paper, an approach to solving the advection dominated atmospheric mass transport problem which adaptively constructs and updates the computational mesh is implemented and analyzed, and the formulation of the mesh adaptation algorithm allows for information from other model processes as well as transport to influence mesh refinement.

ReportDOI
29 Jun 1999
TL;DR: Several new methods are presented for the capturing and tracking of material boundary interfaces using the general Volume Of Fluid approach, and vary from simple flow aligned algorithms to more complex geometric modeling.
Abstract: Several new methods are presented for the capturing and tracking of material boundary interfaces. All methods belong to the general Volume Of Fluid (VOF) approach, and vary from simple flow aligned algorithms to more complex geometric modeling. The performance of the different methods is evaluated by solving the advection equations for a variant of the canonical multi-fluid ''ball & jacks'' problem.