(Website of a former member, who has recently left MathCCES)

MATHCCES

Department of Mathematics

RWTH Aachen University

Schinkelstr. 2

D-52062 Aachen

Germany

Office: Rogowski building, room 328b

Phone: +49(0)241 80 98664

Email: .

- I started as
**PostDoc researcher**in the group of Prof. Klein at FU Berlin in October 2017 with a Joint Postdoctoral Fellowship of FU Berlin and Peking University

- Project 1: Artificial Neural Network (at FU Berlin)
- Project 4: Numerical Methods for Flow Simulations

- Hyperbolic PDEs
- Numerics for non-conservative hyperbolic PDE systems
- Moment methods for rarefied gases
- Non-classical quadrature and Quadrature-based projections

By appointment. Please contact me via e-mail.

I am PostDoc in the group of Prof. Klein at Freie Universität Berlin.
I studied at RWTH Aachen University and did my PhD in Mathematics with Prof. Torrilhon.

- since
**10/2017**PostDoc at Freie Universität Berlin

**7/2017**PhD in Applied Computational Mathematics at MathCCES, RWTH Aachen University

**09/2013**M.Sc. in Computational Engineering Science at RWTH Aachen University

**03/2012**B.Sc. in Computational Engineering Science at RWTH Aachen University

I am a member of the SIAM Student Chapter at RWTH Aachen, for more information see SIAMSC RWTH Aachen

- Mathematik für Geowissenschaftler II, SS 2018, FU Berlin
- Gewöhnliche Differentialgleichungen, SS 2017, RWTH Aachen University
- Mathematische Grundlagen III (CES), WS 2016/2017, RWTH Aachen University
- Analysis für Informatiker, WS 2015/2016, RWTH Aachen University
- Mathematische Grundlagen II (CES), SS 2015, RWTH Aachen University
- Mathematical Models in Science and Engineering (PDEs), SS 2014, RWTH Aachen University

- Mathematische Grundlagen I (CES), WS 2013/2014, RWTH Aachen University
- Mathematische Grundlagen I-V (CES), 2009-2012, student teaching assistant, RWTH Aachen University

**Diagram notation for the derivation of hyperbolic moment systems**, Julian Koellermeier, Yuwei Fan, submitted

**Two-Dimensional Simulation of Rarefied Gas Flows Using Quadrature-Based Moment Equations**, Julian Koellermeier, Manuel Torrilhon, SIAM Multiscale Model. Simul., 16(2), 1059–1084, 2018 .**Numerical Study of Partially Conservative Moment Equations in Kinetic Theory**, J. Köllermeier, M. Torrilhon, Commun. in Comput. Phys., 21(4), p. 981-1011, 2017 .**Numerical solution of hyperbolic moment models for the Boltzmann equation**, J. Köllermeier, M. Torrilhon, Eur. J. Mech. B-Fluids, 64, p. 41-46, 2017 .**Model Reduction of Kinetic Equations by Operator Projection**, Y. Fan, J. Köllermeier, J. Li, R. Li, M. Torrilhon, J. Stat. Phys., 162(2), p. 457-486, 2016 .**A Framework for Hyperbolic Approximation of Kinetic Equations Using Quadrature-Based Projection Methods**, J. Köllermeier, R. P. Schärer, M. Torrilhon, Kinet. Relat. Mod., 5(3) p.531-549, 2014 .**Solving a Non-Linear Partial Differential Equation for the Simulation of Tumour Oxygenation**, J. Köllermeier, L. Kusch, T. Lajewski, SIAM Undergraduate Research Online, 5, p.128-147, 2012, available online at SIURO

**Simplified Hyperbolic Moment Equations**, J. Köllermeier, M. Torrilhon, In: Klingenberg C., Westdickenberg M. (eds) Theory, Numerics and Applications of Hyperbolic Problems II. HYP 2016. Springer Proceedings in Mathematics & Statistics, vol 237, 2018 .**Shock structure simulation using hyperbolic moment models in partially-conservative form**, J. Köllermeier, M. Torrilhon, Proceedings of the 30th Symposium on Rarefied Gas Dynamics, AIP Conf. Proc. 1786, 140004, 2016 .**On new hyperbolic moment models for the Boltzmann equation**, J. Köllermeier, M. Torrilhon, Conference Proceedings of the YIC GACM 2015, Publication Server of RWTH Aachen University, p.142-145, 2015 .**Hyperbolic moment equations using quadrature-based projection methods**, J. Köllermeier, M. Torrilhon, Proceedings of the 29th Symposium on Rarefied Gas Dynamics, AIP Conf. Proc. 1628, p.626-633, 2014 .

**Derivation and Numerical Solution of Hyperbolic Moment Equations for Rarefied Gas Flows**, Julian Koellermeier, dissertation, RWTH Aachen University, 2017 .**Hyperbolic Approximation of Kinetic Equations Using Quadrature-Based Projection Methods**, J. Köllermeier, Master thesis, RWTH Aachen University, 2013 .**Stochastic Particle Methods for Rarefied Gases**, J. Köllermeier, seminar work, RWTH Aachen University, 2013 .**Comparison of Time-Stepping Schemes for Compressible Gas Dynamics**, J. Köllermeier, Bachelor thesis, RWTH Aachen University, 2012 .**Implementation of Implicit Solution Techniques for Non-Equilibrium Hypersonic Flows**, J. Köllermeier, von Karman Institute for Fluid Dynamics, Short Training Report 2012-04, 2012 .**Asymptotic Accuracy for Boundary Value Problems**, J. Köllermeier, M. Torrilhon, project work, RWTH Aachen University, 2011 .**Virtual tumour project**, J. Köllermeier, L. Kusch, T. Lajewski, project work, RWTH Aachen University, 2011 .

**Hyperbolic Moment Models for Rarefied Gases: Recent Developments and Future Projects**, seminar talk, Peking University, October 17th, 2018 .**Adaptive Simulation of Rarefied Gases Using Hierarchical Moment Models**, International Congress of Mathematicians, Rio de Janeiro, August 3rd, 2018 .**Improving the Convergence of Moment Methods for Rarefied Gases Using Filters**, 31st International Symposium on Rarefed Gas Dynamics, Glasgow, July 26th, 2018 .**Accelerated convergence of moment models for the Boltzmann equation using filters**, KU Leuven, Leuven, June 14th, 2018 .**Atmospheric Reentry and Numerical Simulation of Rarefied Gases**, University of Ottawa, Ottawa, March 29th, 2018 .**Numerical simulation of rarefied gases using continuum models**, Brown University, Providence, March 23rd, 2018 .**On model adaptive simulations of rarefied gases using hyperbolic moment models**, Von Karman Institute, Brussels, January 22nd, 2018 .**Derivation and Numerical Solution of Hyperbolic Moment Equations for Rarefied Gas Flows**, invited speaker at Workshop on Moment Methods in Kinetic Theory III, Peking University, September 27th, 2017 .**Derivation and Numerical Solution of Hyperbolic Moment Equations for Rarefied Gas Flows**, PhD defense, RWTH Aachen University, July 26th, 2017 .**Numerical Simulation of Rarefied Gases using Hyperbolic Moment Equations in Partially-Conservative Form**, Free University Berlin, May 18th, 2017 .**On a New Diagram Notation for the Derivation of Hyperbolic Moment Models**, Stanford University, March 17th, 2017 .**Higher order numerical schemes for non-conservative hyperbolic PDEs on 2D unstructured grids**, SIAM Conference on Computational Science and Engineering, Atlanta, March 1st, 2017 .**Extension of standard fluid dynamics equations: Simulation of rarefied gases using hyperbolic moment models**, poster presentation at SIAM Conference on Computational Science and Engineering, Atlanta, February 28th, 2017 .**Atmospheric Entry - Technology, Mathematical Model and Simulation**, SIAM Student Chapter Seminar on Applied Mathematics, RWTH Aachen University, August 26th, 2016 .**On the Derivation and Numerical Solution of Stable Hyperbolic Moment Equations**, 16th International Conference on Hyperbolic Problems, Aachen, August 1st, 2016 .**Numerical Convergence Study of Hyperbolic Moment Models in Partially-Conservative Form**, 30th International Symposium on Rarefed Gas Dynamics, Victoria, July 12th, 2016 .**On the Stability of Hyperbolic Moment Equations**, Beijing Computational Science Research Center, Beijing, May 24th, 2016 .**Atmospheric Reentry Simulation**, Berlin, April 26th, 2016 .**Numerical Solution of Hyperbolic Moment Models for the Boltzmann Equation**, 2nd European Conference on Non-equilibrium Gas Flows, TU Eindhoven, December 10th, 2015 .**On the Stability and Numerical Solution of Partially Conservative Hyperbolic Moment Equations**, lunch talk seminar at MathCCES, RWTH Aachen University, November 26th, 2015 .**Reentry - From Science Fiction to Simulation**, Bonn, November 1st, 2015 .**Comparison of Numerical Solutions for the Boltzmann Equation and Different Moment Models**, Chinese Academy of Sciences, Beijing, October 12th, 2015 .**Numerical Solution of Hyperbolic Moment Equations for the Boltzmann Equation**, Peking University, Beijing, October 8th, 2015 .**Numerical solution of hyperbolic moment models for the Boltzmann equation in non-conservative form**, poster presentation at AC.CES conference, RWTH Aachen University, July 23rd, 2015 .**On new hyperbolic moment models for the Boltzmann equation**, ECCOMAS Young Investigators Conference, RWTH Aachen University, July 21st, 2015 .**Atmospheric Reentry - Mathematical Modelling of Rarefied Gases**, Heidelberg, April 24th, 2015 .**On the Numerical Solution of the Boltzmann Equation Using Quadrature-Based Projection Methods**, poster presentation at SIAM Conference on Computational Science and Engineering, Salt Lake City, March 15th, 2015 .**On an Operator Projection Framework for Kinetic Equations**, lunch talk seminar at MathCCES, RWTH Aachen University, December 11th, 2014 .**Quadrature-Based Moment Method for the Boltzmann Equation**, poster presentation at Workshop on Moment Methods in Kinetic Theory II, Toronto, October 15th, 2014 .**Atmospheric Reentry - Introduction, Mathematical Model and Simulation**, Gummersbach, August 23rd, 2014 .**Adaptive and Hyperbolic Quadrature-Based Moment Method for the Boltzmann Equation**, Peking University, Beijing, August 18th, 2014 .**Comparison of Hyperbolic Moment Models for the Boltzmann Equation**, China Three Gorges University, Yichang, August 8th, 2014 .**Hyperbolic Moment Equations Using Quadrature-Based Projection Methods**, 29th International Symposium on Rarefed Gas Dynamics, Xi'an, July 14th, 2014 .**Hyperbolic Approximation of Kinetic Equations Using Quadrature-Based Projection Methods**, Master Thesis defense at MathCCES, RWTH Aachen University, September 25th, 2013 .**Stochastic Particle Methods for Rarefifed Gases**, seminar talk at MathCCES, RWTH Aachen University, February 1st, 2013 .**Comparison of Time Stepping Techniques for Compressible Gas Dynamics**, Bachelor Thesis defense at MathCCES, RWTH Aachen University, May 3rd, 2012 .**Implementation of Implicit Solution Techniques for Non-equilibrium Hypersonic Flows**, Internship Report at von Karman Institute, Brussels, December 15th, 2011 and at MathCCES, RWTH Aachen University, January 12th, 2012 .**Solving a non-linear partial differential equation for the simulation of tumour oxygenation**, Karolinska Institute, Stockholm, September 19th, 2011 .**Virtual tumour project**, project presentation/lunch talk at MathCCES, RWTH Aachen University, May 26th, 2011 .

**Shallow water equations in presence of topography**, Maren Casfor, seminar thesis, FU Berlin, June 2017**A Higher-Order Finite Volume Method for Non-Conservative Equations on 2D Unstructured Quadrilateral Grids**, Yannick Dueren, seminar work, RWTH Aachen University, November 2016 .**Development and Implementation of an Algorithm for the Analysis of Loaded Filter Media**, Yannick Dueren, Bachelor thesis, RWTH Aachen University, March 2016 (confidential)**Implementation of Adaptive Time Stepping Techniques for Flow Simulations**, Rachna Shetty, Bachelor thesis, BITS Pilani, India, December 2015 .**Unstructured quad grid generation and grid management for flow simulations**, Laurin Scholz, Bachelor thesis, RWTH Aachen University, October 2014 .