scholarly journals Solution of the inverse radiation problem for anisotropically scattering medium using the control volume finite element method

2010 ◽  
Vol 14 (2) ◽  
pp. 373-382 ◽  
Author(s):  
Hajer Grissa ◽  
Faouzi Askri ◽  
Fethi Albouchi ◽  
Nasrrallah Ben
Keyword(s):  
Finite Element Method ◽  
Inverse Problem ◽  
Finite Element ◽  
Control Volume ◽  
Measured Temperature ◽  
Scattering Medium ◽  
Unknown Parameters ◽  
Radiation Problem ◽  
Control Volume Finite Element ◽  
Element Method

In this paper, an inverse analysis is performed for the estimation of radiative parameters from the measured temperature profile in an absorbing, emitting, and anisotropically scattering medium. The control volume finite element method is employed to solve the direct problem in a 3-D rectangular furnace. The inverse problem is formulated as an optimization problem between the calculated and the experimental data and the Levenberg-Marquardt method is used for its solution. The sensitivity analysis is made in order to determine whether it is possible to identify the parameters. Also, the effects of angular and spatial grid numbers and the initial guesses on the accuracy of the inverse problem are investigated. This method combination, which is applied for the first time to solve 3-D inverse radiation problem, has been found to accurately predict the unknown parameters.

Prediction of Permeability Tensor for Plain Woven Fabric by Using Control Volume Finite Element Method

2003 ◽  
Vol 11 (6) ◽  
pp. 465-476 ◽  
Author(s):  
Y. S. Song ◽  
K. Chung ◽  
T. J. Kang ◽  
J. R. Youn
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Control Volume ◽  
Three Dimensional ◽  
Woven Fabrics ◽  
Permeability Tensor ◽  
Woven Fabric ◽  
Stacking Order ◽  
Control Volume Finite Element ◽  
Element Method

The complete prediction of the second order permeability tensor for a three dimensional multi-axial preform is critical if we are to model and design the manufacturing process for composites by considering resin flow through a multi-axial fiber structure. In this study, the in-plane and transverse permeabilities for a woven fabric were predicted numerically by the coupled flow model, which combines microscopic and macroscopic flows. The microscopic and macroscopic flows were calculated by using 3-D CVFEM(control volume finite element method) for micro and macro unit cells. To avoid a checkerboard pressure field and improve the efficiency of numerical computation, a new interpolation function for velocity is proposed on the basis of analytical solutions. The permeability of a plain woven fabric was measured by means of an unidirectional flow experiment and compared with the permeability calculated numerically. Reverse and simple stacking of plain woven fabrics were taken into account and the relationship between the permeability and the structures of the preform such as the fiber volume fraction and stacking order is identified. Unlike other studies, the current study was based on a more realistic three dimensional unit cell. It was observed that in-plane flow is more dominant than transverse flow within the woven perform, and the effect of the stacking order of a multi-layered preform was negligible.

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