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Control Volume Method (control + volume_method)
Selected AbstractsThermal radiation effects of a high-temperature developing laminar flow in a tubeHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 5 2004Xin-Lin Xia Abstract The thermal radiation effects of a high-temperature developing laminar flow in a tube are investigated numerically. The two-dimensional steady flow and heat transfer are considered for an absorbing-emitting gray medium, whose density is dependent on the temperature. The governing equations of the coupled process are simultaneously solved by the discrete ordinate method combined with the control volume method. For a moderate optical thickness, the velocity distribution, the temperature distribution, and the radial heat flux distribution in the medium as well as the heat flux distribution on the tube wall are presented and discussed. The results show that the thermal radiation effects of a high-temperature medium are significant under a moderate optical thickness. The flow and convective heat transfer are weakened, and the development of temperature distribution is accelerated noticeably. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(5): 299,306, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20018 [source] Study of non-Fickian diffusion problems with the potential field in the cylindrical co-ordinate systemINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2003Han-Taw Chen Abstract The present study applies a hybrid numerical scheme of the Laplace transform technique and the control volume method in conjunction with the hyperbolic shape functions to investigate the effect of a potential field on the one-dimensional non-Fickian diffusion problems in the cylindrical co-ordinate system. The Laplace transform method is used to remove the time-dependent terms in the governing differential equation and the boundary conditions, and then the resulting equations are discretized by the control volume scheme. The primary difficulty in dealing with the present problem is the suppression of numerical oscillations in the vicinity of sharp discontinuities. Results show that the present numerical results do not exhibit numerical oscillations and the potential field plays an important role in the present problem. The strength of the jump discontinuity can be reduced by increasing the value of the potential gradient. The propagation speed of mass wave is independent of the potential gradient and the boundary condition. Copyright © 2003 John Wiley & Sons, Ltd. [source] Automatic construction of non-obtuse boundary and/or interface Delaunay triangulations for control volume methodsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 7 2002Nancy Hitschfeld Abstract A Delaunay mesh without triangles having obtuse angles opposite to boundary and interface edges (obtuse boundary/interface triangles) is the basic requirement for problems solved using the control volume method. In this paper we discuss postprocess algorithms that allow the elimination of obtuse boundary/interface triangles of any constrained Delaunay triangulation with minimum angle ,. This is performed by the Delaunay insertion of a finite number of boundary and/or interface points. Techniques for the elimination of two kinds of obtuse boundary/interface triangles are discussed in detail: 1-edge obtuse triangles, which have a boundary/interface (constrained) longest edge; and 2-edge obtuse triangles, which have both their longest and second longest edge over the boundary/interface. More complex patterns of obtuse boundary/interface triangles, namely chains of 2-edge constrained triangles forming a saw diagram and clusters of triangles that have constrained edges sharing a common vertex are managed by using a generalization of the above techniques. Examples of the use of these techniques for semiconductor device applications and a discussion on their generalization to 3-dimensions (3D) are also included. Copyright © 2002 John Wiley & Sons, Ltd. [source] Flows through horizontal channels of porous materialsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 10 2003A.K. Al-Hadhrami Abstract In this paper, the control volume method (CVM) with the staggered grid system is utilized to solve the two-dimensional Brinkman equation for different configurations of porous media in a horizontal channel. The values of the permeability of sand and clear fluid are considered when performing several numerical investigations which enable the evaluation of the behaviour of the flow through regions that mathematically model some geological features (faults/fractures) present in oil reservoirs or groundwater flows. We have found that the convergence of the CVM can be achieved within a reasonable number of iterations when there is a gap present between a partial barrier of low Darcy number and the channel boundary. However, a complete barrier across the channel results in a very high resistance and hence there is a large pressure drop which causes difficulties in convergence. In order to improve the rate of convergence in such situations, an average pressure correction (APC) technique, which is based on global mass conservation, is developed. The use of this technique, along with the CVM, can rapidly build up the pressure drop across such a barrier and hence dramatically improve the rate of convergence of the iterative scheme. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||