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Article
Publication date: 4 October 2018

Alice de Jesus Kozakevicius, Dia Zeidan, Alex A. Schmidt and Stefan Jakobsson

The purpose of this work is to present the implementation of weighted essentially non-oscillatory (WENO) wavelet methods for solving multiphase flow problems. The particular…

215

Abstract

Purpose

The purpose of this work is to present the implementation of weighted essentially non-oscillatory (WENO) wavelet methods for solving multiphase flow problems. The particular interest is gas–liquid two-phase mixture with velocity non-equilibrium. Numerical simulations are carried out on different scenarios of one-dimensional Riemann problems for gas–liquid flows. Results are validated and qualitatively compared with solutions provided by other standard numerical methods.

Design/methodology/approach

This paper extends the framework of WENO wavelet adaptive method to a fully hyperbolic two-phase flow model in a conservative form. The grid adaptivity in each time step is provided by the application of a thresholded interpolating wavelet transform. This facilitates the construction of a small yet effective sparse point representation of the solution. The method of Lax–Friedrich flux splitting is used to resolve the spatial operator in which the flux derivatives are approximated by the WENO scheme.

Findings

Hyperbolic models of two-phase flow in conservative form are efficiently solved, as shocks and rarefaction waves are precisely captured by the chosen methodology. Substantial computational gains are obtained through the grid reduction feature while maintaining the quality of the solutions. The results indicate that WENO wavelet methods are robust and sufficient to accurately simulate gas–liquid mixtures.

Originality/value

Resolution of two-phase flows is rarely studied using WENO wavelet methods. It is the first time such a study on the relative velocity is reported in two-phase flows using such methods.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 9
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 25 December 2023

Fatima Harbate, Nouh Izem, Mohammed Seaid and Dia Zeidan

The purpose of this paper is to investigate the two-phase flow problems involving gas–liquid mixture.

57

Abstract

Purpose

The purpose of this paper is to investigate the two-phase flow problems involving gas–liquid mixture.

Design/methodology/approach

The governed equations consist of a range of conservation laws modeling a classification of two-phase flow phenomena subjected to a velocity nonequilibrium for the gas–liquid mixture. Effects of the relative velocity are accounted for in the present model by a kinetic constitutive relation coupled to a collection of specific equations governing mass and volume fractions for the gas phase. Unlike many two-phase models, the considered system is fully hyperbolic and fully conservative. The suggested relaxation approach switches a nonlinear hyperbolic system into a semilinear model that includes a source relaxation term and characteristic linear properties. Notably, this model can be solved numerically without the use of Riemann solvers or linear iterations. For accurate time integration, a high-resolution spatial reconstruction and a Runge–Kutta scheme with decreasing total variation are used to discretize the relaxation system.

Findings

The method is used in addressing various nonequilibrium two-phase flow problems, accompanied by a comparative study of different reconstructions. The numerical results demonstrate the suggested relaxation method’s high-resolution capabilities, affirming its proficiency in delivering accurate simulations for flow regimes characterized by strong shocks.

Originality/value

While relaxation methods exhibit notable performance and competitive features, as far as we are aware, there has been no endeavor to address nonequilibrium two-phase flow problems using these methods.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 34 no. 3
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 1 September 2000

B.S.V. Patnaik, P.A.A. Narayana and K.N. Seetharamu

Flow past an isolated circular cylinder and two cylinders in tandem is numerically simulated, under the influence of buoyancy aiding and opposing the flow. A modified velocity…

1458

Abstract

Flow past an isolated circular cylinder and two cylinders in tandem is numerically simulated, under the influence of buoyancy aiding and opposing the flow. A modified velocity correction method is employed, which has second order accuracy in both space and time. The influence of buoyancy on the temporal fluid flow patterns is investigated, with respect to streamlines, isotherms and streaklines. Comparisons are made with respect to mean center line velocities, drag coefficients, Strouhal number and streakline patterns. Degeneration of naturally occurring Kármán vortex street into a twin eddy pattern is noticed in the Reynolds number (Re) range of 41‐200, under buoyancy aided convection. On the contrary, buoyancy opposed convection could trigger vortex shedding even at a low Re range of 20‐40, where only twin eddies are found in the natural wake. Temporal evolution of unsteady eddy patterns is visualized by means of numerical particle release (NPR). Zones of vortex shedding and twin vortices are demarcated on a plot of Richardson number against Strouhal number. Root mean square (RMS) lift coefficients (CL,RMS) and average drag coefficient (\overline Cd) are obtained as a function of Richardson number (Ri).

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 10 no. 6
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 1 April 1996

B.S.V.P. Patnaik, K.N. Seetharamu and P.A. Aswatha Narayana

A finite element method is used to study the effect of flow past acircular cylinder with an integral wake splitter. A fractional step algorithmis employed to solve the…

193

Abstract

A finite element method is used to study the effect of flow past a circular cylinder with an integral wake splitter. A fractional step algorithm is employed to solve the Navier‐Stokes and Energy equations with a Galerkin weighted residual formulation. The vortex shedding process is simulated and the effect of splitter addition on the time period of shedding is studied at a Reynolds number of 200 and a blockage ratio of 0.25. The effect of splitter and the Strouhal number and heat transfer augmentation per unit pressure drop has been investigated.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 6 no. 4
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 1 September 1997

Rama Subba Reddy Gorla, A. Slaouti and H.S. Takhar

Presents a non‐similar boundary layer analysis for the problem of mixed convection in power‐law type non‐Newtonian fluids along an isothermal vertical plate with surface mass…

276

Abstract

Presents a non‐similar boundary layer analysis for the problem of mixed convection in power‐law type non‐Newtonian fluids along an isothermal vertical plate with surface mass transfer. Solves the transformed governing laws numerically using a finite difference method. Presents numerical results for the details of the velocity and temperature fields. Discusses the effect of suction and injection as well as the viscosity index on the surface heat transfer rate.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 7 no. 6
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 1 August 1998

Rama Subba Reddy Gorla, A. Slaouti and H.S. Takhar

A boundary layer solution is presented to the steady free convection from a vertical plate with uniform surface heat flux conditions and immersed in a micropolar fluid. Numerical…

313

Abstract

A boundary layer solution is presented to the steady free convection from a vertical plate with uniform surface heat flux conditions and immersed in a micropolar fluid. Numerical solutions for governing nonsimilar boundary layer equations are presented for a range of values of the material properties and Prandtl number of the fluid. An asymptotic solution is developed for large distances away from the leading edge.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 8 no. 5
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 3 April 2018

Omar Abu Arqub

The purpose of this study is to introduce the reproducing kernel algorithm for treating classes of time-fractional partial differential equations subject to Robin boundary…

471

Abstract

Purpose

The purpose of this study is to introduce the reproducing kernel algorithm for treating classes of time-fractional partial differential equations subject to Robin boundary conditions with parameters derivative arising in fluid flows, fluid dynamics, groundwater hydrology, conservation of energy, heat conduction and electric circuit.

Design/methodology/approach

The method provides appropriate representation of the solutions in convergent series formula with accurately computable components. This representation is given in the W(Ω) and H(Ω) inner product spaces, while the computation of the required grid points relies on the R(y,s) (x, t) and r(y,s) (x, t) reproducing kernel functions.

Findings

Numerical simulation with different order derivatives degree is done including linear and nonlinear terms that are acquired by interrupting the n-term of the exact solutions. Computational results showed that the proposed algorithm is competitive in terms of the quality of the solutions found and is very valid for solving such time-fractional models.

Research limitations/implications

Future work includes the application of the reproducing kernel algorithm to highly nonlinear time-fractional partial differential equations such as those arising in single and multiphase flows. The results will be published in forthcoming papers.

Practical implications

The study included a description of fundamental reproducing kernel algorithm and the concepts of convergence, and error behavior for the reproducing kernel algorithm solvers. Results obtained by the proposed algorithm are found to outperform in terms of accuracy, generality and applicability.

Social implications

Developing analytical and numerical methods for the solutions of time-fractional partial differential equations is a very important task owing to their practical interest.

Originality/value

This study, for the first time, presents reproducing kernel algorithm for obtaining the numerical solutions of some certain classes of Robin time-fractional partial differential equations. An efficient construction is provided to obtain the numerical solutions for the equations, along with an existence proof of the exact solutions based upon the reproducing kernel theory.

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Article
Publication date: 16 July 2019

Omar Abu Arqub

The subject of the fractional calculus theory has gained considerable popularity and importance due to their attractive applications in widespread fields of physics and…

241

Abstract

Purpose

The subject of the fractional calculus theory has gained considerable popularity and importance due to their attractive applications in widespread fields of physics and engineering. The purpose of this paper is to present results on the numerical simulation for time-fractional partial differential equations arising in transonic multiphase flows, which are described by the Tricomi and the Keldysh equations of Robin functions types.

Design/methodology/approach

Those resulting mathematical models are solved by using the reproducing kernel method, which provide appropriate solutions in term of infinite series formula. Convergence analysis, error estimations and error bounds under some hypotheses, which provide the theoretical basis of the proposed method are also discussed.

Findings

The dynamical properties of these numerical solutions are discussed and the profiles of several representative numerical solutions are illustrated. Finally, the prospects of the gained results and the method are discussed through academic validations.

Originality/value

In this paper and for the first time: the authors presented results on the numerical simulation for classes of time-fractional PDEs such as those found in the transonic multiphase flows. The authors applied the reproducing kernel method systematically for the numerical solutions of time-fractional Tricomi and Keldysh equations subject to Robin functions types.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 11
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 12 October 2021

Linbo Yang, Joo Seng Tan and Chenjing Gan

Rapidly changing technological and marketing environments challenge the survival of business organizations. Developing dynamic capability is critical in helping companies respond…

574

Abstract

Purpose

Rapidly changing technological and marketing environments challenge the survival of business organizations. Developing dynamic capability is critical in helping companies respond to today's turbulent environments. Thus, fruitful studies on the antecedents of dynamic capability have been conducted. However, in the context of the supply chain, little is known about the factors that can be harmful to dynamic capability. Drawing on the theory of cooperation and competition, the first purpose of this study is to examine the relationship between independent goal interdependence with suppliers and dynamic capability by focusing on the mediating role of supplier integration. Combining the information processing theory and transaction cost economics with the theory of cooperation and competition, the second purpose of this study is to discuss and test the moderating role of internal integration.

Design/methodology/approach

Using a carefully designed questionnaire, a large-scale survey was employed to collect data in China. The senior manager (e.g. president, vice president, chief executive officer [CEO], executive or purchasing manager) of each company was asked to participate in our survey. The final valid sample in our survey consisted of 233 companies. Hierarchical multiple regression statistical analysis and bias-corrected bootstrapping methods were applied to test the correlation, mediation, moderation and moderated mediation relationships between variables.

Findings

The authors found that independent goal interdependence negatively influences dynamic capability through frustrating supplier integration. In addition, the moderated mediation model analysis shows that internal integration weakens the positive direct effect of supplier integration on dynamic capability while neutralizing the negative indirect effect of independent goal interdependence on dynamic capability. The theoretical and managerial implications of these results are discussed.

Originality/value

First, starting from the goal interdependence and supply chain management perspectives, this research not only is consistent with remote theoretical research that explains why interdependence among organizations influences the capability to enhance competitive advantage but also incorporates relevant internal and external factors that influence dynamic capability. Second, by proposing an innovative boundary factor – internal integration – this study also contributes to adjusting the predictions of the theory of cooperation and competition. Third, focusing specifically on the negative antecedent of dynamic capability can provide a better understanding of the antecedents that cause companies to have weakened dynamic capability.

Details

Asia Pacific Journal of Marketing and Logistics, vol. 34 no. 7
Type: Research Article
ISSN: 1355-5855

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Article
Publication date: 15 May 2009

R. Ravindran, Satyajit Roy and E. Momoniat

The purpose of this paper is to study the steady mixed convection flow over a vertical cone in the presence of surface mass transfer when the axis of the cone is inline with the…

459

Abstract

Purpose

The purpose of this paper is to study the steady mixed convection flow over a vertical cone in the presence of surface mass transfer when the axis of the cone is inline with the flow.

Design/methodology/approach

In this case, the numerical difficulties to obtain the non‐similar solution are overcome by applying an implicit finite difference scheme in combination with the quasilinearization technique.

Findings

Numerical results are reported here to display the effects of Prandtl number, buoyancy and mass transfer (injection and suction) parameters at different stream‐wise locations on velocity and temperature profiles, and on skin friction and heat transfer coefficients.

Research limitations/implications

Thermo‐physical properties of the fluid in the flow model are assumed to be constant except the density variations causing a body force term in the momentum equation. The Boussinesq approximation is invoked for the fluid properties to relate the density changes to temperature changes and to couple in this way the temperature field to the flow field.

Practical implications

Convective heat transfer over a stationary cone is important for the thermal design of various types of industrial equipments such as heat exchangers, conisters for nuclear waste disposal, nuclear reactor cooling systems and geothermal reservoirs, etc.

Originality/value

The combined effects of thermal diffusion and surface mass transfer on a vertical cone has been studied.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 19 no. 3/4
Type: Research Article
ISSN: 0961-5539

Keywords

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