scholarly journals Numerical Study of Highly Viscous Fluid Sloshing in the Real-Scale Membrane-Type Tank

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4244 ◽  
Author(s):  
Shuo Mi ◽  
Zongliu Huang ◽  
Xin Jin ◽  
Mahdi Tabatabaei Malazi ◽  
Mingming Liu
Keyword(s):  
Free Surface ◽  
Numerical Model ◽  
Stokes Equations ◽  
Numerical Study ◽  
Full Scale ◽  
Navier Stokes ◽  
Fast Fourier Transformation ◽  
Two Phase ◽  
Wide Range ◽  
Membrane Type

The highly viscous liquid (glycerin) sloshing is investigated numerically in this study. The full-scale membrane-type tank is considered. The numerical investigation is performed by applying a two-phase numerical model based on the spatially averaged Navier-Stokes equations. Firstly, the numerical model is validated against the available numerical model and a self-conducted experiment then is applied to systematically investigate the full-scale sloshing. In this study, two filling levels (50% and 70% of the tank height) are considered. The fluid kinematic viscosity is fixed at a value being 6.0 × 10−5 m2/s with comparative value to that of the crude oil. A wide range of forcing periods varying from 8.0 s to 12.0 s are used to identify the response process of pressures as well as free surface displacements. The pressures are analyzed along with breaking free surface snapshots and corresponding pressure distributions. The slamming effects are also demonstrated. Finally, the frequency response is further identified by the fast Fourier transformation technology.

scholarly journals Experimental and Numerical Study on Water Filling and Air Expelling Process in a Pipe with Multiple Air Valves under Water Slow Filling Condition

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2511
Author(s):  
Jintao Liu ◽  
Di Xu ◽  
Shaohui Zhang ◽  
Meijian Bai
Keyword(s):  
Numerical Model ◽  
Stokes Equations ◽  
Numerical Study ◽  
Practical Method ◽  
Navier Stokes ◽  
Physical Processes ◽  
Two Phase ◽  
Saint Venant Equations ◽  
Water Filling ◽  
Air Valve

This paper investigates the physical processes involved in the water filling and air expelling process of a pipe with multiple air valves under water slow filling condition, and develops a fully coupledwater–air two-phase stratified numerical model for simulating the process. In this model, the Saint-Venant equations and the Vertical Average Navier–Stokes equations (VANS) are respectively applied to describe the water and air in pipe, and the air valve model is introduced into the VANS equations of air as the source term. The finite-volume method and implicit dual time-stepping method (IDTS) with two-order accuracy are simultaneously used to solve this numerical model to realize the full coupling between water and air movement. Then, the model is validated by using the experimental data of the pressure evolution in pipe and the air velocity evolution of air valves, which respectively characterize the water filling and air expelling process. The results show that the model performs well in capturing the physical processes, and a reasonable agreement is obtained between numerical and experimental results. This agreement demonstrates that the proposed model in this paper offers a practical method for simulating water filling and air expelling process in a pipe with multiple air valves under water slow filling condition.

scholarly journals Numerical Study of Violent Impact Flow Using a CIP-Based Model

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Qiao-ling Ji ◽  
Xi-zeng Zhao ◽  
Sheng Dong
Keyword(s):  
Free Surface ◽  
Numerical Model ◽  
Large Scale ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Small Scale ◽  
Surface Boundary ◽  
Two Phase ◽  
Constrained Interpolation

A two-phase flow model is developed to study violent impact flow problem. The model governed by the Navier-Stokes equations with free surface boundary conditions is solved by a Constrained Interpolation Profile (CIP)-based high-order finite difference method on a fixed Cartesian grid system. The free surface is immersed in the computation domain and expressed by a one-fluid density function. An accurate Volume of Fluid (VOF)-type scheme, the Tangent of Hyperbola for Interface Capturing (THINC), is combined for the free surface treatment. Results of another two free surface capturing methods, the original VOF and CIP, are also presented for comparison. The validity and utility of the numerical model are demonstrated by applying it to two dam-break problems: a small-scale two-dimensional (2D) and three-dimensional (3D) full scale simulations and a large-scale 2D simulation. Main attention is paid to the water elevations and impact pressure, and the numerical results show relatively good agreement with available experimental measurements. It is shown that the present numerical model can give a satisfactory prediction for violent impact flow.

Scouring Below Pipelines: The Role of Vorticity and Turbulence

2010 ◽  
Author(s):  
Matteo Mattioli ◽  
Alessandro Mancinelli ◽  
Giuseppina Colicchio ◽  
Maurizio Brocchini
Keyword(s):  
Numerical Model ◽  
Lift Force ◽  
Stokes Equations ◽  
Numerical Study ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Offshore Pipeline ◽  
Temporal Averaging ◽  
Force Components

A numerical study on the turbulence and vorticity of local scour underneath an offshore pipeline placed on a non-cohesive sandy seabed and forced by a steady flow current is presented. The numerical model solves the Navier-Stokes equations using an innovative Level Set technique. The model predicts the behavior of the movable sediments through both drift and lift force components. Mean and turbulent flow quantities were extracted by temporal averaging. Results on the distribution and evolution of turbulent kinetic energy and vorticity will be illustrated at the conference.

Simulation of Fluid Flow Through a Granular Bed

2006 ◽  
Author(s):  
Arezou Jafari ◽  
S. Mohammad Mousavi
Keyword(s):  
Stokes Equations ◽  
Numerical Study ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Packed Bed ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Wide Range ◽  
Duct Geometry ◽  
Flow Through

Numerical study of flow through random packing of non-overlapping spheres in a cylindrical geometry is investigated. Dimensionless pressure drop has been studied for a fluid through the porous media at moderate Reynolds numbers (based on pore permeability and interstitial fluid velocity), and numerical solution of Navier-Stokes equations in three dimensional porous packed bed illustrated in excellent agreement with those reported by Macdonald [1979] in the range of Reynolds number studied. The results compare to the previous work (Soleymani et al., 2002) show more accurate conclusion because the problem of channeling in a duct geometry. By injection of solute into the system, the dispersivity over a wide range of flow rate has been investigated. It is shown that the lateral fluid dispersion coefficients can be calculated by comparing the concentration profiles of solute obtained by numerical simulations and those derived analytically by solving the macroscopic dispersion equation for the present geometry.

scholarly journals Numerical Study of Local Scour around a Submarine Pipeline with a Spoiler Using a Symmetry Boundary Condition

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1847
Author(s):  
Chuan Zhou ◽  
Jianhua Li ◽  
Jun Wang ◽  
Guoqiang Tang
Keyword(s):  
Numerical Model ◽  
Stokes Equations ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Numerical Results ◽  
Local Scour ◽  
Navier Stokes ◽  
Scour Depth ◽  
Submarine Pipeline ◽  
The Mean

A two-dimensional numerical model for solving the Navier–Stokes equations was developed to investigate the local scour around a submarine pipeline with a spoiler. Both the suspended load and the bed load were considered in the present numerical model. The focus of the present study is to investigate the effects of the spoiler length on the hydrodynamic forces on the pipeline and the spoiler as well as the local scour around the submarine pipeline. The corresponding numerical results show that the mean drag coefficients of the pipeline and the spoiler increase with the increase of the spoiler length. As for the mean lift coefficient, a general decreasing trend with the increasing spoiler length is observed for the pipeline. However, the mean lift coefficient of the spoiler first increases and then decreases with the increasing spoiler length. In addition, it is found that a larger spoiler length leads to a deeper scour depth, and an empirical equation was proposed for predicting the non-dimensional scour depth of submarine pipelines with non-dimensional spoiler length based on the numerical results.

CFD Simulations of a Semi-Submersible With Absorbing Boundary Conditions

2009 ◽  
Author(s):  
Peter R. Wellens ◽  
Roel Luppes ◽  
Arthur E. P. Veldman ◽  
Mart J. A. Borsboom
Keyword(s):  
Boundary Conditions ◽  
Stokes Equations ◽  
Computing Time ◽  
Height Function ◽  
Absorbing Boundary Conditions ◽  
Navier Stokes ◽  
Two Phase ◽  
Absorbing Boundary ◽  
Wide Range ◽  
Grid Points

The CFD tool ComFLOW is suitable for simulations of two-phase flows in offshore applications. ComFLOW solves the Navier-Stokes equations in both water and (compressible) air. The water surface is advected through a Volume-of-Fluid method, with a height-function approach for improved accuracy. By employing Absorbing Boundary Conditions (ABC), boundaries can be located relatively close to an object, without influencing outgoing waves or generating numerical reflections that affect the waves inside the flow domain. Traditionally, boundaries are located far from the obstacle to avoid reflections; even when numerical damping zones are used. Hence, with the ABC approach less grid points are required for the same accuracy, which reduces the computing time considerably. Simulations of a semi-submersible model are compared to measurements. The overall agreement is reasonably good, for a wide range of wave conditions. The ABC performs well; numerical reflections are almost absent. Moreover, computing times reduce with a factor four compared to damping zone techniques.

Impingement Heat Transfer of Free-Surface Liquid Jets

2002 ◽  
Author(s):  
Albert Y. Tong
Keyword(s):  
Heat Transfer ◽  
Free Surface ◽  
Stokes Equations ◽  
Numerical Study ◽  
Navier Stokes ◽  
Liquid Jets ◽  
Liquid Jet ◽  
Stagnation Region ◽  
Navier Stokes Equations ◽  
Impingement Heat Transfer

The problem of convective heat transfer of a circular liquid jet impinging onto a substrate is studied numerically. The objective of the study is to understand the hydrodynamics and heat transfer of the impingement process. The Navier-Stokes equations are solved using a finite-volume formulation. The free surface of the jet is tracked by the volume-of-fluid method. The energy equation is modeled by using an enthalpy-based formulation. Detailed flow fields as well as free surface contours and pressure distributions on the substrate have been obtained. Local Nusselt number variations along the solid surface have also been calculated. The effects of several key parameters on the hydrodynamics and heat transfer of an impinging liquid jet have been examined. It has been found that the jet-inlet velocity profile and jet elevation have a significant effect on the hydrodynamics and heat transfer, particularly in the stagnation region, of an impinging jet. The numerical results have been compared with experimental data obtained from the literature. The close agreement supports the validity of the numerical study.

Numerical Simulation of Wave Propagation Over Submerged Composite Breakwaters Using the Immersed Boundary Method

2014 ◽  
Author(s):  
Theofano I. Koutrouveli ◽  
Athanassios A. Dimas
Keyword(s):  
Free Surface ◽  
Numerical Model ◽  
Immersed Boundary Method ◽  
Stokes Equations ◽  
Splitting Method ◽  
Staggered Grid ◽  
Immersed Boundary ◽  
Two Phase ◽  
Boundary Method ◽  
Two Dimensional Flow

The two-dimensional flow induced by waves over submerged breakwaters of two different shapes is studied by means of a two-phase (water and air) Navier-Stokes equations solver. A time-splitting method is used for the temporal discretization, while the spatial discretization is based on the use of finite differences in a Cartesian staggered grid. The implementation of the boundary conditions at solid surfaces, as well as the treatment of the free surface is performed using the immersed boundary method where the breakwater, the seabed and the free surface are boundaries immersed in the numerical grid. The numerical model was applied on the propagation and breaking over a constant slope beach, as well as on the propagation and nonlinear transformation of waves over two types of submerged breakwaters, i.e., trapezoidal and composite (with berm in the up-slope side). The results of the numerical model reveal that the presence of the berm reduces the transmission coefficient and this reduction increases with the decrease of the berm depth of submergence.

Numerical Study of Incompressible Flow About Transversely Oscillating Cylinder Pairs

2004 ◽  
Vol 126 (4) ◽  
pp. 310-317 ◽  
Author(s):  
W. Jester ◽  
Y. Kallinderis
Keyword(s):  
Incompressible Flow ◽  
Stokes Equations ◽  
Numerical Study ◽  
Structural Response ◽  
Secondary Peak ◽  
Navier Stokes ◽  
Flow Induced Vibration ◽  
Oscillating Cylinder ◽  
Navier Stokes Equations ◽  
Wide Range

A numerical investigation of incompressible flow about transversely oscillating cylinder pairs is performed. Both tandem and side-by-side arrangements undergoing both flow-induced and forced transverse oscillations are considered. A second-order projection scheme is used to solve the 2-D incompressible Navier Stokes equations and a staggered approach is used to couple flow and structural response. Automatic mesh deformation and adaptation are used to handle arbitrary motion of the bodies. Comparisons with experimental results indicate that the present numerical method can capture complex interference and flow–structure interaction phenomena. Specifically, results are presented that demonstrate wake galloping effects, in which a cylinder in the wake of another experiences large flow-induced vibration over a wide range of flow velocities, and the presence of an experimentally observed secondary peak in the flow-induced vibration of rigidly connected cylinders in a tandem arrangement. An explanation of this secondary peak is provided by employing appropriate visualization of the unsteady flow. Results for forced oscillation of a pair of cylinders in a side-by-side arrangement are also presented that show the effect of phase angle on the wake structure behind the cylinder pair.

Numerical Study of Liquid Slug Stability During Adiabatic Two Phase Flow Inside a Minichannel

2007 ◽  
Author(s):  
A. Mukherjee ◽  
J. S. Allen
Keyword(s):  
Contact Angle ◽  
Continuity Equation ◽  
Stokes Equations ◽  
Numerical Study ◽  
Navier Stokes ◽  
Phase Flow ◽  
Liquid Slug ◽  
Two Phase ◽  
Navier Stokes Equations ◽  
Liquid Plug

The present study is performed to analyze stability of a liquid meniscus inside a microchannel. A liquid plug is placed inside a microchannel and the shape and stability of upstream and downstream interfaces have been studied for different airflow rates. The thickness of the liquid plug and the contact angle has been varied systematically. In the numerical model the complete Navier-Stokes equations along with continuity equation are solved using the SIMPLER method. The liquid vapor interface is captured using the level set technique. The liquid plug is seen to move downstream along with the air and surface instabilities are noted at the upstream and downstream interfaces. At low contact angle, water is found to accumulate at the channel corners due to capillary forces causing the slug to disintegrate. The numerical results are found to be qualitatively similar to experimental data.

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