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Untitled - Teknik Kelautan / ITB

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Application of Finite Volume Cell Center Method with Wet and<br />

Dry Treatment in Hydrodynamic Flow Modeling<br />

Bobby Minola Ginting 1 , Dantje K. Natakusumah 2 , Dhemi Harlan 2 , Herli<br />

Ginting 3<br />

1 Faculty of Engineering, Parahyangan Catholic University<br />

2 Faculty of Civil and Environmental Engineering, Bandung Institute of Technology<br />

3 Faculty of Mathematics and Science, University of North Sumatera<br />

Email: bobbyminola.g@unpar.ac.id, dhemi@si.itb.ac.id<br />

Abstract. Numerical scheme of Finite Volume Cell-Center with Artificial Viscosity<br />

as spatial discretization and Runge Kutta Fourth Order as time stepping is proposed<br />

to solve two dimensional shallow water equations in conservation forms which cover<br />

mass and momentum conservation in both directions. The unstructured curvilinear<br />

mesh is used in domain discretization, while the hybrid formula is applied to Runge<br />

Kutta Fourth Order in time stepping. With this hybrid formula, the artificial term is<br />

only computed once therefore the computational cost can be minimized. The<br />

artificial viscosity is formed by combination of Laplacian and Biharmonic operator<br />

to handle numerical instabilities. The function of Laplacian operator is to stabilize<br />

solution around shock wave phenomenon, and Biharmonic operator is to omit the<br />

wiggle solution. The Biharmonic operator is turned off when hydraulic jump<br />

phenomenon occurred, and conversely, turned on when it disappeared.<br />

Characteristic method is used in boundary condition treatment to determine the<br />

velocity both in x and y directions when water elevation is specified. Wall boundary<br />

condition is treated with normal velocity at the wall is zero condition. Wet and dry<br />

treatment is applied especially for domain with initially dry condition by set a value<br />

limiter for minimum depth. Once the water depth reaches this value, the velocities in<br />

both directions are set to be zero.This program was built and successfully applied for<br />

some hydrodynamic cases. For some initially dry-bed cases, the wet and dry<br />

treatment gives the good results. This method is simple, accurate, efficient and<br />

conservative. It can be concluded that this method shows promise to be applied in<br />

other hydrodynamic cases, especially for complex domain cases.<br />

Keywords: artificial viscosity, finite volume method, hybrid Runge-Kutta, shallow<br />

water equations<br />

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