Numerical Simulation Lab

Lab manager: Prof. Dr. Georg Wimmer

The laboratory deals with the numerical simulation and optimization of processes in nature and technology. In particular, the numerical calculation of electromagnetic fields is important in the development of many technical products, such as electric motors, generators, solenoid valves, batteries, isolators. Mathematically interesting questions arise with regard to discretization methods, accuracy and error estimates, orders of convergence, parallelization of the algorithms on high-performance computers. Bachelor's, project and Master's theses in this area can be awarded.

Computing cluster

The laboratory includes a computing cluster (CentOS Linux Server Release 7.6) consisting of

1 master - 1x Intel Xeon E5-1620 v3 (3.5GHz, 4 cores), 128GB RAM
2 nodes (overall 48 cores) - per node:
- 2x Intel Xeon E5-2680 v3 (2.5GHz, each CPU 12 cores)
- 256GB RAM
3 nodes (overall 96 cores) - per node:
- 2x Intel Xeon Gold 5218 (2.3GHz, each CPU 16 cores)
- 384GB RAM

Computing cluster with one master and five nodes.

Prof. Georg Wimmer and one ITSC-employee in front of a server rack filled with components. — Structure of the computing cluster in 2016. Left: Prof. Georg Wimmer, right: ITSC staff.

Matlab Distributed Computing Server (MDCS) is installed for parallel computing with Matlab. The local computer requires the Parallel Computing Toolbox.

Image clarifying how computation on a head node is administered by a client and distributed to several worker nodes. — Matlab Distributed Computing (source: MathWorks).

Diagram and table on computation time comparison of the sequential and parallel FEM algorithm (created by S. Volz). — Computation time comparison of the sequential and parallel FEM algorithm (created by S. Volz).

Differential forms

A C++ implementation is used to calculate the electromagnetic fields, which is based on the theory of differential forms. It is taken into account that different physical quantities have different continuity, derivative and evaluation properties. For example, the electric potential (0-form) is totally continuous, the derivative is the gradient and the evaluation takes place at one point.

In contrast, the magnetic flux density (2-form) is normally continuous, the derivative is the divergence, and the evaluation is given by a surface integral. Furthermore, the order of the discretization error, which arises due to the finite fineness of the grid, is significant.

Graphics of potential distribution in a plate capacitor, where red represents the positive and blue the negative charge. With increasing distance from the plates, the colours are becoming weaker and turn green (potential zero) — Potential distribution in a plate capacitor.

Graphics of magnetic flux density of a current-carrying coil by coloured magnetic field lines, which are very dense within the coild (=red), and are far apart outside of the coil (=blue). — Magnetic flux density of a current-carrying coil.

Graphic representation in a diagram of a discretization error (L2 norm) as a function of the grid fineness (logarithmic). in Abhängigkeit der Gitterfeinheit (logarithmisch). The order emerges from the negative slope of the regression line. — Discretization error (L2 norm) as a function of grid fineness (logarithmic). The order emerges from the negative slope of the regression line.

Graphic representation in a diagram of a discretization error as a function of grid fineness (logarithmic). The order emerges from the negative slope of the regression line. — Discretization error (Q norm) as a function of grid fineness (logarithmic). The order emerges from the negative slope of the regression line.

Projects

Projects have been carried out with Bundeswehr Research Institute for Protective Technologies and CBRN Protection and Jiaotong University Shanghai, School of Electronic Information and Electrical Engineering.

Error investigations of finite element methods in adaptive grid structures
Calculation of RLCG parameters, RLCG 参数的计算方法
Qualiy assurance concept for 2D FEM solver for electrostatics problems

Applications

Examples of electromagnetic simulations are...

Threedimensional graphics - TEAM13 problem: Nonlinear magnetostatic simulation. — TEAM13 problem: Nonlinear magnetostatic simulation.

Threedimensional graphics - TEAM20 problem: Nonlinear magnetostatic simulation. — TEAM20 problem: nonlinear magnetostatic simulation.

Graphics cross-section of a electric motor — Motor geometry

Graphics magnetic flux lines in a motor. — Magnetic flux lines in a motor.

Current density distribution in conductors with harmonic excitation at 10kHz. From left to right: 3D model, reduced 2D model with grid, matrix fill, current density distribution. — Current density distribution in conductors with harmonic excitation at 10kHz.
From left to right: 3D model, reduced 2D model with grid, matrix fill, current density distribution.

3D CAD-construction and simulation with Solidworks

The University of Applied Sciences Würzburg-Schweinfurt is official academic certification provider of various Solidworks (SWX) exams (Solidworks Associate Mechanical Design, Professional Advanced Sheet Metal, Surfacing, Weldments, Associate Electrical, Simulation and more) since 2020. For more information on Solidworks exams click here: Link1,
Link2,
Link3.

The general elective (AWPF) "3D-CAD-Construction –und Simulation with Solidworks" which is usually offered in summer enables students to pass the exam Certified SOLIDWORKS Associate in Mechanical Design ACADEMIC VERSION (CSWA). The CSWA - Academic Exam is provided in the following languages: English, French, German, Italian, Korean, Spanish, Chinese S, Chinese T, Japanese, Brazilian and Portuguese.

CAD model carnival ride — Solidworks assembly (source: SWX 3D Experience World).

CAD model skid steer with pallet fork — Solidworks assembly (source: SWX 3D Experience World)

Across-the-audience view of a conference room of a speeker and slide "3D Experience World 2020 - A New Dimension with Experience" — SWX 3D Experience World in Nashville, TN, USA.

[Translate to Englisch:] Blick in einen Konferenzsaal über das Publikum auf eine Leinwand mit Vortragendem und Grafik "Automatic elimination of recirculation to improve fluid performance" — [Translate to Englisch:] SWX 3D Experience World in Nashville, TN, USA.