Browsing by Author "Lin, Chao-An"

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An immersed boundary technique for simulating complex flows with rigid boundary
(2007-02-01)
Su, Shen-Wei
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Lai, Ming-Chih
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Lin, Chao-An
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應用數學系
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Department of Applied Mathematics
A new immersed boundary (IB) technique for the simulation of flow interacting with solid boundary is presented. The present formulation employs a mixture of Eulerian and Lagrangian variables, where the solid boundary is represented by discrete Lagrangian markers embedding in and exerting forces to the Eulerian fluid domain. The interactions between the Lagrangian markers and the fluid variables are linked by a simple discretized delta function. The numerical integration is based on a second-order fractional step method under the staggered grid spatial framework. Based on the direct momentum forcing on the Eulerian grids, a new force formulation on the Lagrangian marker is proposed, which ensures the satisfaction of the no-slip boundary condition on the immersed boundary in the intermediate time step. This forcing procedure involves solving a banded linear system of equations whose unknowns consist of the boundary forces on the Lagrangian markers; thus, the order of the unknowns is one-dimensional lower than the fluid variables. Numerical experiments show that the stability limit is not altered by the proposed force formulation, though the second-order accuracy of the adopted numerical scheme is degraded to 1.5 order. Four different test problems are simulated using the present technique (rotating ring flow, lid-driven cavity and flows over a stationary cylinder and an in-line oscillating cylinder), and the results are compared with previous experimental and numerical results. The numerical evidences show the accuracy and the capability of the proposed method for solving complex geometry flow problems both with stationary and moving boundaries. (c) 2005 Elsevier Ltd. All rights reserved.
Diagnosing Bladder Outlet Obstruction Assessed By Computational Fluid Dynamics and Medical Imaging Technique
(2010-06-01)
Yang, Cheng-Hsiu
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Chen, Wei-Ju
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Chen, Wen-Lih
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Lin, Chao-An
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Ching, Yu-Tai
Bladder outlet obstruction (BOO) suggestive benign prostatic hyperplasia is a common disease in elder men. The present golden standard diagnostics, however, is an invasive method, named pressure-flow studies. The aim of the study is to develop a non-invasive procedure, which combines computational fluid dynamics and the medical imaging techniques, as a new approach for diagnosing bladder outlet obstruction. Based on the computed tomography images, the lower urinary tract system is reconstructed. The flow resistance within the urinary tract is predicted using the computational fluid dynamics. It is shown that this quantity displayed a high correlation (r = 0.86) with the golden standard parameter, BOO index, i.e. clinically measured data for patients with BOO. This indicates that the present method may be potentially valid substitute for invasive BOO index.
Finite elements in flow problems 2015, Taiwan
(2017-01-05)
Lin, Chao-An
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Bazilevs, Yuri
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Brummelen, E. Harald
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Chen, Ching-Yao
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Takizawa, Kenji
Selected Papers from the 3rd International Workshop on Heat Transfer Advances for Energy Conservation and Pollution Control (IWHT2015)
(2018-01-01)
Wang, Qiu-Wang
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Hung, Tzu-Chen
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Chen, Yitung
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Lin, Chao-An
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Wang, Chi-Chuan