Biomedical subjects

Taehun Lee

Publications and source records attributed to Taehun Lee.

3 recordsLinked to original sources

PubMed2006

Eliminating parasitic currents in the lattice Boltzmann equation method for nonideal gases.

A formulation of the intermolecular force in the nonideal-gas lattice Boltzmann equation method is examined. Discretization errors in the computation of the intermolecular force cause parasitic currents. These currents can be eliminated to roundoff if the potential form of the intermolecular force is used with compact isotropic discretization. Numerical tests confirm the elimination of the parasitic currents.

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PubMed2005

Rarefaction and compressibility effects of the lattice-Boltzmann-equation method in a gas microchannel.

A wall equilibrium boundary condition for an implicit lattice-Boltzmann-equation method is proposed to simulate gas flows in a microchannel with rough surface on the characteristic length of gas molecules. The boundary condition is based on the assumption that impinging molecules reach equilibrium with the surface. The molecular mean free path used to define the Knudsen number is determined by the lattice speed and the relaxation time of the lattice-Boltzmann equation. With the wall equilibrium boundary condition and the appropriate relation defined for the Knudsen number and the relaxation time, the computed slip velocity and nonlinear pressure distribution along the microchannel are in excellent agreement with analytical solutions.

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PubMed2003

Pressure evolution lattice-Boltzmann-equation method for two-phase flow with phase change.

A lattice-Boltzmann-equation method for nonideal gases augmented by the pressure evolution equation is proposed to simulate isothermal two-phase fluid flow with phase change. The pressure evolution equation is derived by taking time derivative of the equation of state for nonideal gases. Unlike previous methods that use the equation of state to update pressure, the pressure field is evolved using the pressure evolution equation. The new approach has two advantages. First, it can avoid spurious pressure fluctuations at phase interfaces that develop owing to the pressure update by the equation of state, thus improving numerical stability of the method. Second, it permits compressibility of the fluid at phase interfaces when phase change occurs due to pressurization and depressurization. The proposed method is applied to simulate an isothermal phase change process. The numerical result is in excellent agreement with the analytical solution.

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