**报告人/Speaker:** Wolfgang Bangerth, Colorado State University

**报告题目/Title:**Simulating complex flows in the Earth mantle

**时间/Date & Time:**May 17, 2018, 16:00—17:00

**地点/Venue:**北京科学与工程计算研究院M842报告厅

**报告摘要/Abstract：**

On long enough time scales, the Earthmantle (the region between the rigid plates at the surface and the liquid metalouter core at depth) behaves like a fluid. While it moves only a few entimetersper year, the large length scales nevertheless lead to very large Rayleighnumbers and, consequently, very complex and expensive numerical simulations. Atthe same time, given the inaccessibility of the Earth mantle to directexperimental observation implies that numerical simulation is one of the fewavailable tools to elucidate what exactly is going on in the mantle, how itaffects the long-term evolution of Earth's thermal and chemical structure, aswell as what drives and sustains plate motion.

I will here review the approach we havetaken in building the state-of-the-art open source solver ASPECT (see http://aspect.geodynamics.org) to simulate realistic conditions in the Earthand other celestial bodies. ASPECT is built using some of the most widely usedand best software libraries for common tasks, such as deal.II for mesh handlingand discretization, p4est for parallel partitioning and rebalancing, and Trilinosfor linear algebra. In this talk, I will focus on the choices we have maderegarding the numerical methods used in ASPECT, and in particular on theinterplay between higher order discretizations on adaptive meshes, linear andnonlinear solvers, optimal preconditioners, and approaches to scale tothousands of processor cores. All of these are necessary for simulations thatcan answer geophysical questions.

**报告人简介/About the speaker:**

Wolfgang Bangerth, professor in theDepartment of Mathematics at Colorado State University. Ph.D. in Heidelberg, briefly working at ETHZürich (Switzerland), and three years as a Postdoctoral Research Fellow at theUniversity of Texas at Austin (with joint positions at both the Institute forComputational Sciences and Engineering and at the Institute for Geophysics), Hewas previously a Professor in the Department of Mathematics at Texas A&MUniversity. His work is developing methods and widelyusable software for the numerical solution of partial differential equations bythe finite element method.