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Semi-implicit Backward-Difference Formulae (SBDF) Methods for First-Order<br />

Nonlinear Ordinary Differential Equations (ODEs)<br />

Nurul Amira Eliana Binti Mohd Rahimi<br />

Supervisor: Dr. Loy Kak Choon<br />

Bachelor of Science (Computational Mathematics)<br />

School of Informatics and Applied Mathematics<br />

We proposed SBDF methods to solve nonlinear 1 st -order ordinary differential equations<br />

(ODEs). SBDF methods which treat the linear term implicitly and the nonlinear term<br />

explicitly are known to be more stable than fully explicit methods and at the same time<br />

avoiding Newton’s method. However, they are less stable than the implicit methods. SBDF<br />

methods are very efficient ODE solvers with a properly chosen step size. We found two<br />

suitable well-posed test cases (test-problem and manufactured-solution) for the purpose<br />

of numerical illustration. We derived SBDF methods using Taylor’s expansion and showed<br />

the order of convergence theoretically. The exact solutions of the two test cases are<br />

available for numerical benchmarking. We implement the numerical schemes using<br />

Octave for two test cases using SBDF methods with 1 st -, 2 nd - and 3 rd -order of accuracy.<br />

Also, the order of convergence was reproduced numerically and the CPU time for each<br />

SBDF method is compared for efficiency analysis.<br />

988 | UMT UNDERGRADUATE RESEARCH DAY 2018

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