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Article
Publication date: 1 August 2016

Atta Sojoudi, Marzieh Khezerloo, Suvash C Saha and Yuantong Gu

The purpose of this paper is to numerically investigate two dimensional steady state convective heat transfer in a differentially heated square cavity with constant temperatures…

Abstract

Purpose

The purpose of this paper is to numerically investigate two dimensional steady state convective heat transfer in a differentially heated square cavity with constant temperatures and an inner rotating cylinder. The gap between the cylinder and the enclosure walls is filled with power law non-Newtonian fluid.

Design/methodology/approach

Finite volume-based CFD software, Fluent (Ansys 15.0) is used to solve the governing equations. Attribution of the various flow parameters of fluid flow and heat transfer are investigated including Rayleigh number, Prandtl number, power law index, the cylinder radius and the angular rotational speed.

Findings

Outcomes are reported in terms of isotherms, streamlines and average Nusselt number (Nu) of the heated wall for various considered here.

Research limitations/implications

A detailed investigates is needed in the context of 3D flow. This will be a part of the future work.

Practical implications

The effect of a rotating cylinder on heat transfer and fluid flow in a differentially heated rectangular enclosure filled with power law non-Newtonian fluid has practical importance in the process industry.

Originality/value

The results of this study may be of some interest to the researchers of the field of chemical or process engineers.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 2 November 2015

Zhicheng He, Guangyao Li, Guiyong Zhang, Gui-Rong Liu, Yuantong Gu and Eric Li

In this work, an SFEM is proposed for solving acoustic problems by redistributing the entries in the mass matrix to “tune” the balance between “stiffness” and “mass” of discrete…

Abstract

Purpose

In this work, an SFEM is proposed for solving acoustic problems by redistributing the entries in the mass matrix to “tune” the balance between “stiffness” and “mass” of discrete equation systems, aiming to minimize the dispersion error. The paper aims to discuss this issue.

Design/methodology/approach

This is done by simply shifting the four integration points’ locations when computing the entries of the mass matrix in the scheme of SFEM, while ensuring the mass conservation. The proposed method is devised for bilinear quadratic elements.

Findings

The balance between “stiffness” and “mass” of discrete equation systems is critically important in simulating wave propagation problems such as acoustics. A formula is also derived for possibly the best mass redistribution in terms of minimizing dispersion error reduction. Both theoretical and numerical examples demonstrate that the present method possesses distinct advantages compared with the conventional SFEM using the same quadrilateral mesh.

Originality/value

After introducing the mass-redistribution technique, the magnitude of the leading relative dispersion error (the quadratic term) of MR-SFEM is bounded by (5/8), which is much smaller than that of original SFEM models with traditional mass matrix (13/4) and consistence mass matrix (2). Owing to properly turning the balancing between stiffness and mass, the MR-SFEM achieves higher accuracy and much better natural eigenfrequencies prediction than the original SFEM does.

Details

Engineering Computations, vol. 32 no. 8
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 22 August 2008

Y.T. Gu and Q. Wang

The purpose of this paper is to develop an effective numerical approach to assess the nonlinear dynamic responses of a near‐bed submarine pipeline.

Abstract

Purpose

The purpose of this paper is to develop an effective numerical approach to assess the nonlinear dynamic responses of a near‐bed submarine pipeline.

Design/methodology/approach

A coupled numerical approach is proposed in this paper to assess the nonlinear dynamic responses of this pipeline. The boundary‐element method is first used to get the nonlinear dynamic fluid loading induced by the asymmetric flow. The meshless technique is used to discretize the structure of the pipeline. A numerical example is first presented to verify the effectivity of the present method. Then, the coupled technique is used to simulate the nonlinear dynamic fluid‐structure interaction problem of a near‐bed pipeline. A Newton‐Raphson iteration procedure is used herein to solve the nonlinear system of equations, and the Newmark method is adopted for the time integration.

Findings

The presence of seabed results in a large negative lift on a pipeline in a horizontal current. Studies reveal that there exists a critical current velocity, above which the pipeline will become instable, and the critical velocity is significantly affected by the initial gap from the pipeline to the seabed.

Originality/value

The near‐bed submarine pipeline is a widely used structure in marine engineering. This paper originally develops a numerical approach to model this special fluid‐structure interaction problem. It has demonstrated by the examples that the present approach is very effective and has good potential in the practical applications.

Details

Engineering Computations, vol. 25 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

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