
2週內演講

Colloquium, 中央大學數學系 楊肅煜教授
Thursday, May 25, 15:10—16:00 數學系3174
Title: HA DirectForcing Immersed Boundary Projection Method for FluidSolid Interaction Problems Abstract: In this talk, we will introduce a simple and novel directforcing immersed boundary projection method in conjunction with a predictioncorrection process for simulating the dynamics of fluidsolid interaction problems, in which each immersed solid object can be stationary or moving in the fluid. The method is mainly based on the introduction of a virtual force, which is distributed only on the immersed solid bodies and appended to the fluid momentum equations to accommodate the boundary conditions at the immersed solid boundaries. Although this method is a twostage approach, the computational cost of the correction stage is rather cheap, since the associated discrete linear systems need to be solved in the correction stage are same with that in the prediction stage, except the righthand side data terms. Such a predictioncorrection procedure can be iterated to form a more general method, if necessary. Numerical experiments of several benchmark problems are performed to illustrate the simplicity and efficient performance of the proposed method. Convergence tests show that the accuracy of the velocity field is superlinear in space in all the 1norm, 2norm, and maximum norm. We also find that our numerical results are in very good agreement with the previous works in the literature and one correction at each time step seems good enough. This is joint work with TzyyLeng Horng, PoWen Hsieh and ChengShu You.

Colloquium, 中央大學數學系 洪盟凱教授
Friday, June 2, 16:10—17:00 數學系3174
Title: KellerSegel Equations with Nonlinear Interactions and Small Diffusions Abstract: In this talk, we consider the onedimensional KellerSegel equations with small diffusion and nonlinear interaction between cells and chemical signals. We study the existence of the traveling pulses by the geometric singular perturbations and the trapping region. We show such traveling pulse is unstable by the spectral analysis.





