Linear and nonlinear instabilities of a co-current gas-liquid flow between two inclined plates analyzed using the Navier–Stokes equations

2020 ◽  
Vol 122 ◽  
pp. 103159
Author(s):  
Yu.Ya. Trifonov
Keyword(s):  
Liquid Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Linear And Nonlinear ◽  
Gas Liquid Flow ◽  
Inclined Plates

VOF Simulations of Gas Bubbles Motion in a Reciprocally Stirred Flow

2010 ◽  
Vol 44-47 ◽  
pp. 2494-2498
Author(s):  
Hong Liu ◽  
Mao Zhao Xie ◽  
Hong Chao Yin ◽  
De Qing Wang
Keyword(s):  
Surface Tension ◽  
Flow Field ◽  
Numerical Simulations ◽  
Liquid Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equations ◽  
Mesh Method ◽  
Gas Liquid Flow

This paper reports progress in the numerical simulations of movement and the coalescence of two neighbor bubbles (leading and trailing bubble) in a reciprocally stirred liquid flow field. The full Navier-Stokes equations are solved by the volume-of fluid (VOF) method for tracking the interface between the bubble and the liquid flow. A dynamic mesh method was used to predict the gas-liquid flow in a two-dimensional foaming tank. Results indicate that the motion and merge behavior of the bubbles is dominantly influenced by the initial locations and the sizes of the bubbles as well as by the surface tension, while the reciprocating effect is insignificant.

scholarly journals Direct Numerical Simulation of Liquid Flow in a Horizontal Microchannel

2005 ◽  
Author(s):  
Cenk Evren Ku¨krer ◽  
I˙lker Tarı
Keyword(s):  
Liquid Flow ◽  
Energy Equation ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Micro Channel ◽  
Governing Equations ◽  
Qualitative Comparison ◽  
Navier Stokes Equations ◽  
Axial Conduction ◽  
Micro Channels

Numerical Simulations of liquid flow in a micro-channel between two horizontal plates are performed. The channel is infinite in streamwise and spanwise directions and its height is taken as 3.1×10−4 m which falls within the dimension ranges of micro-channels. The Navier-Stokes equations with the addition of Brinkman number (Br) to the energy equation are used as the governing equations and a spectral methods based approach is applied to obtain the required accuracy to handle liquid flow in the micro-channel. It is known for micro-channels that Br combines the effects of conduction and viscous dissipation in liquids and is also a way of comparing the importance of later relative to former. A laminar flow of a liquid in a micro-channel shows different characteristics compared to a similar flow in a macro-channel. To observe the differences, three different cases are run over each of a range of Reynolds numbers: one with no axial conduction assumption that correspond to a case similar to macro-channel flow, another case with axial conduction included in the energy equation to simulate one of the main differences and lastly a case with inclusion of Br number in the governing equations. The results are compared with each other to see the effects of axial conduction and Br inclusion. A qualitative comparison is made with the previous results in literature.

Reynolds-Averaged Navier–Stokes Equations for Turbulence Modeling

2009 ◽  
Vol 62 (4) ◽  
Author(s):  
Giancarlo Alfonsi
Keyword(s):  
Turbulent Flows ◽  
Incompressible Flows ◽  
Stokes Equations ◽  
Nonlinear Models ◽  
Turbulence Models ◽  
Equation Model ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Linear And Nonlinear ◽  
Reynolds Averaged Navier Stokes

The approach of Reynolds-averaged Navier–Stokes equations (RANS) for the modeling of turbulent flows is reviewed. The subject is mainly considered in the limit of incompressible flows with constant properties. After the introduction of the concept of Reynolds decomposition and averaging, different classes of RANS turbulence models are presented, and, in particular, zero-equation models, one-equation models (besides a half-equation model), two-equation models (with reference to the tensor representation used for a model, both linear and nonlinear models are considered), stress-equation models (with reference to the pressure-strain correlation, both linear and nonlinear models are considered) and algebraic-stress models. For each of the abovementioned class of models, the most widely-used modeling techniques and closures are reported. The unsteady RANS approach is also discussed and a section is devoted to hybrid RANS/large methods.

scholarly journals Comparison between numerical and experimental water-in-oil dispersion in a microchannel

2017 ◽  
Author(s):  
Dominique Tarlet ◽  
Philippe Desjonquères ◽  
Thibault Ménard ◽  
Jérôme Bellettre
Keyword(s):  
Experimental Data ◽  
Level Set ◽  
Liquid Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Experimental Setup ◽  
Navier Stokes Equations ◽  
Dispersion Process ◽  
Liquid Dispersion ◽  
Precise Knowledge

The dispersion of water inside a flow of oil is investigated in a microfluidic device, producing a water-in-oilemulsion. The liquid–liquid flow mainly differs from those presented in existing literature through its high capillary number (between 3 and 14), and in the head-on collision between water and oil streams. By comparing with experimental data, numerical simulations can provide more information about the topology of the flow. A coupled Volume of Fluid and Level Set method (CLSVOF) is used to treat the interface between both phases and incompressible Navier-Stokes equations are solved. Three set of parameters, close to those in the experimental setup, are investigated to compare experimental and numerical results. The comparison between experiments and simulation provides a precise knowledge of the liquid-liquid dispersion process and the overall flow patternwithin the microfluidic device.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4717

scholarly journals Numerical Simulation of Disturbance Evolution in the Supersonic Boundary Layer over an Expansion Corner

2021 ◽  
Vol 56 (5) ◽  
pp. 645-656
Author(s):  
P. V. Chuvakhov ◽  
I. V. Egorov
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Stokes Equations ◽  
Supersonic Boundary Layer ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Stabilization ◽  
Stabilization Effect ◽  
Aerodynamic Experiment ◽  
Linear And Nonlinear

Abstract— The linear and nonlinear stages of disturbance development in the supersonic boundary layer over a 10° expansion corner is investigated numerically within the framework of Navier—Stokes equations for Mach number 3. The effect of sudden flow expansion on the disturbance evolution is analyzed. The flow stabilization effect observable in the aerodynamic experiment is also discussed.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

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