S. Kunze, P. Perrier, R. Groll, B. Besser, S. Varoutis, A. Lüttge, I. Graur, J. Thöming : Rarefied gas flow in functionalized microchannels; Scientific Reports 14, 8559, Nature 2024


R. Groll, T. Frieler : Validation of DSMC mass flow modeling for transsonic gas flows in micro-propulsion systems; Frontiers in Mechanical Engineering 9, 1217645, Frontiers 2023

A. Haghahenas, S. Hedayatpour, R. Groll : Prediction of particle-laden pipe flows using deep neural network models; Physics of Fluids 35, 083320, AIP 2023

T. Frieler, R. Groll : Micro-nozzle flow and thrust prediction with high density ratio using DSMC selection limiter; Frontiers in Space Technology 4, 1114188, Frontiers 2023


A. Haghshenas, A. Bohlen, D. Tyralla, R. Groll : The relevance of wall roughness modeling for simulation of powder flows; The International Journal of Advanced Manufactoring Technology, Springer 2022

A. Bohlen, T. Seefeld, A. Haghshenas, R. Groll : Characterization of the Powder Stream Propagation Behavior of a Discrete Coaxial Nozzle for Laser Metal Deposition; Journal of Laser Application, LIA 2022

A. Haghshenas, R. Groll : Characterization of particle-laden jet flows in inertia-dominated regime; International Journal of Multiphase Flow 157:104245, Elsevier 2022

M. v. Einem, R. Groll, C. Heinicke : Computational modeling of a ventilation concept for a lunar habitat laboratory; Journal of Space Safety Engineering 9(2):145-153, Elsevier 2022

S. Kunze, R. Groll, B. Besser, J. Thöming : Molecular diameters of rarefied gases; Scientific Reports 12:2057, Nature 2022


C. Kühn, R. Groll : picFoam: An OpenFOAM based electrostatic Particle-In-Cell solver; Computer Physics Communications 262:107853, Elsevier 2021


R. Groll, S. Kunze, B. Besser : Correction of Second-Order Slip Condition for higher Knudsen Numbers by Approximation of Free-Molecular Diffusion; Phys. Fluids 32:092008, AiP 2020

M. v. Einem, C. Heinicke, R. Groll : Numerical analysis of the ventilation in a moon habitat laboratory module; IAC20.B3.4-B6.4.10, 71st International Astronautical Congress, IAF 2020


R. Groll : Dynamic selection limiter schemes for high density gradient simulationsof supersonic rarefied gas flows; PAMM 19(1), Wiley 2019


C. Chelem-Mayigue, C. Kühn, R. Groll : Performance investigation of an Argon fueled magneto-plasma dynamic thruster with applied magnetic fields; Journal of Applied Physics, 124:223301 AIP 2018

C. Chelem-Mayigue, R. Groll : Numerical simulation of Argon fuelled self-field magneto-plasma dynamic thrusters using the central-upwind schemes fluxes interpolation; European Journal of Mechanics B/Fluids 72:645-663, Elsevier 2018

T. Frieler, R. Groll : A torsional sub-millinewton thrust balance based on on a spring leaf strain gauge sensor; Review on Scientific Instruments 89:075101 , AIP 2018

P. Liang, R. Groll : , Numerical study of plasma-electrode interaction during arc discharge in a DC Plasma Torch; IEEE Transaction in Plasma Science 46(2):363-372, IEEExplore 2018

R. Groll, C. Kühn : Shear force analysis of an oil-driven grinding tool; Int. Journal on Computational Methods and Engineering Measurements 6(2):231-239, WITpress 2018


C. Chelem-Mayigue, R. Groll : A density-based method with semi-discrete central-upwind schemes for ideal magnetohydrodynamics; Archive of Applied Mechanics 87:667-683, Springer 2017

E. Brinksmeier, B. Orlik, R. Groll, C. Flosky, A. Norbach, K. Leach, J. Gomez : GrindBall - Novel Drive and Bearing Concept for Micro Grinding Tools (https://www.springerprofessional.de/grindball-a-novel-drive-and-bearing-concept-for-micro-grinding-t/12124698); Chapter in: Small Machine Tools for Small Workpieces (Eds. J. P. Wulfsberg, A. Sanders), ISBN: 978-3-319-49267-4, p. 65-85, Springer 2017


R. Groll, J. E. Gomez : Identifying microproduction inaccuracies with Knudsen number depending correction functions; AiP Conf. Proc. 1786:080012, AiP 2016

C. Chelem-Mayigue, R. Groll : Magneto-plasmadynamic thruster modelling with coaxial induced magnetic field; Int. Journal on Computational Methods and Engineering Measurements 4:4, p. 380-392, WITpress 2016

J. E. Gomez, R. Groll : Experimental and numerical study of the pressure drop in transonic micronozzle flows across multiple flow regimes; ASME Digital collection ICNMM2016-7919 (V001T01A001), American Society of Mechanical Engineers, ASME 2016

R. Groll, J.E. Gomez : Calibrating microfluidic pressure correction functions in Laval nozzle flow by eliminating production accuracy influences; PAMM 16(1):581-582, Wiley 2016

C. Chelem-Mayigue, R. Groll : Computational magneto-hydrodynamic modeling of hypersonic flows with resolved shock wave diffusion; PAMM 16(1):621-622, Wiley 2016

J. E. Gomez, R. Groll : Pressure drop and thrust predictions for transonic micronozzle flows; Physics of Fluids 28(2):022008, AiP 2016


T. Brandt, T. Trottenberg, R. Groll, F. Jansen, F. Hey, U. Johann, H. Kersten, C. Braxmaier : Simulation for an improvement of a down-scaled HEMP-Thruster; e-publication: Electronic Rocket Propulsion Society IEPC-2015-90172, ERPS 2015

C. Zimmermann, R.Groll : Computational investigation of thermal boundary layers in a turbulent Rayleigh-Benard problem; Int. Journal of Heat an Fluid Flow 54:276-291, Elsevier 2015

T. Brandt, T. Trottenberg, R. Groll, F. Jansen, F. Hey, U. Johann, H. Kersten, C. Braxmaier : Simulations on the influence of the spatial distribution of source electrons on the plasma in a cusped-field thruster; Eur. Phys. Journal D 69:145, Springer 2015

R. Groll, J. E. Gomez : Computational multi-component modelling of electron transport and ohmic heating inside a micro arc-jet thruster; Transactions on Engineering Sciences 89, p.3-16, ISBN 978-1-84564-946-3, WIT Press 2015


R. Groll : Micro diffuser flow modeling for cold gas propulsion systems, PAMM 14(1):633-640, Wiley 2014

C. Zimmermann, R.Groll : Experimental and numerical and experimental investigation of a Reyleigh-Benard convection affected by Coriolis force; Journal of Flow Control, Measurement and Visualization 2:165-172, ISSN 2329-3322 Scientific Research 2014

C. Zimmermann, R. Groll : Modelling turbulent heat transfer in a natural convection flow, Journal of Applied Mathematics and Physics; ISSN 2327-4352, 2(7):662-670, Scientific Research 2014

R. Groll : Transonic wall-slip analysis for expanding micro diffuser flows for cold gas propulsion systems; ASME electronic publication, Order No. ASME-46278:V001T01A005, ASME 2014

R. Groll, J. E. Gomez : Investigating and modeling the correlation of pressurization and electron acceleration inside a micro arc-jet thruster; ASME electronic publication, Order No. ASME-46278: V001T06A002, ASME2014

T. Brandt, T. Trottenberg, R. Groll, F. Jansen, F. Hey, U. Johann, H. Kersten, C. Braxmaier : Simulation of a down-scaled HEMP-Thruster; 5th German-Russian Conference on Electric Propulsion, Dresden, Germany 2014

T. Brandt, R. Groll, F. Jansen, U. Johann, A. Keller, H. Kersten, C. Braxmaier : Particle-in-Cell simulation of the plasma properties and ion acceleration of a down-scaled HEMP-Thruster; 19th International Spacecraft Propulsion Conference, Cologne, Germany 2014


R. Groll : Modelling plasma flow with particle classes for different charge carriers and neutral particles; Transactions on Engineering Sciences 79:25-34, p.25-34, ISBN 978-1-84564-734-6, WIT Press 2013

E. Brinksmeier, B. Orlik, R. Groll, C. Brandao, A. Norbach, K. Leach : Grindball-Modul zum achsenlosen Mikroschleifen; Ant Journal : Anwendungsnahe Forschung für Antriebstechnik im Maschinenbau 2/2013:14-19, Vereinigte Fachverlage, Mainz 2013

E. Brinksmeier, B. Orlik, R. Groll, C. Brandao, A. Norbach, K. Leach : Grindball: an advanced micro-grinding tool; Production Engineering 7:5, p.469-476, ISBN 0944-6524, Springer 2013

K. Leach, R. Groll : Modelling Abrasion Forces in a Pneumatically Powered Grinding Tool using Compressible Large Eddy Simulation; Journal of Energy and Power Engineering 7:9, p.1634-1643, ISSN 1934-8975, David Publishing 2013

S. Reichel, R. Groll : Numerical Simulation and experimental validation of a hypersonic flow for numerical modulation of re-entry phenomena prediction using adaptive mesh refinement; Int. Journal of Computational Methods and Experimental Measurements 1:4, p. 381-394, WITpress, 2013.

T. Brandt, R. Groll, F. Jansen, U. Johann, A. Keller, H. Kersten, C. Braxmaier : Magnetohydrodynamics and particle-in-cell codes simulation of plasma processes in micro HEMP thrusters; e-publication: Electronic Rocket Propulsion Society, IEPC-2013-145, ERPS 2013


S. Reichel, R. Groll H. J. Rath : Unsteady numerical simulation with adaptive mesh refinement of a hypersonic double-cone geometry for re-entry phenomena prediction; Computational Methods in Applied Science and Engineering 6, No.3747, ISBN: 978-3-9502481-9-7, Wien 2012

K. Leach, R. Groll, H. J. Rath : Large-Eddy Simulation of a Pneumatically Powered Abrading Sphere; Fluid Flow Technologies 15:600-607, ISBN 978-963-08-4586-1, FFT 2012.

C. Zimmermann, R. Groll : Modelling turbulent heat transfer of a Rayleigh-Benard problem with compressible Large-Eddy simulation; Turbulence, Heat and MassTransfer 7:615-622, ISBN 978- 1-56700-301-7, Begell House Inc. 2012

R. Groll, F. Fastabend, H. J. Rath : Modelling Transsonic Flows Through Ring-Shape Thruster Geometries with DSMC; ASME electronic publication, Order No. ASME-44793:195-204, ASME 2012


R. Groll : Heat and mass transfer in evaporating turbulent Drop-laden flow; Transactions on Engineering Sciences 70:129-140, ISBN 978-1-84564-518-1, WIT Press 2011.

R. Groll, T. Schadowski, S. Reichel, H. J. Rath : Computational modelling of transsonic flow in a thermo-electric propulsion system; DLRK 2011 Proceedings, 1479-1480, DGLR 2011.

S. Reichel, R. Groll, H. J. Rath : Experimental Investigation and Numerical Modeling of Electric Heating Rate in a Generic Electric Propulsion System; e-publication: Electronic Rocket Propulsion Society IEPC-2011-063, ERPS 2011

R. Groll : Velocity and Temperature Boundary-Layer Modeling Using Averaged Molecule cluster Transport Equations; IUVSTA 64 Proceedings (Document, Presentation), IUVSTA 2011


R. Groll, H. J. Rath : On Eulerian modelling of microchannel gas flows closing higher statistical moments of molecule velocity; ASME electronic publication, Order No. ASME-54501:407-412, ISBN 978-0-7918-3880-8, E-Lib ISBN: 978-0-7918-5450-1, ASME 2010

R. Groll : Statistical Eulerian diffusion approach of four-way-coupled multiphase systems; Defect and Diffusion Forum 297-301:832-837, Trans Tech Publications Inc. 2010.

R. Groll : On an α-a model describing vaporizing droplet clouds in turbulent flows; SPRAY 2010 Proceedings:128-135, 2010.


R. Groll : Thermodynamic consistence of statistical modelling molecular diffusion, energy flux and entropy production; Turbulence, Heat and Mass Transfer 6:81-86, ISBN 978-1-56700-262-1, Begell House Inc. 2009.

R. Groll : Mathematical modelling on particle diffusion in fluidised beds and dense turbulent two-phase flows; Transactions on Engineering Sciences 63: 241-250, ISBN 978-84564-188-7, WIT Press 2009.

R. Groll, H. J. Rath : Thermodynamics / turbulence analogy modelling dissipating molecular gas flows for high Knudsen numbers; PAMM Vol. 8:10595-10596, doi:10.1002/pamm.2008 , Wiley 2009.

R. Groll, S.Jakirlic, C. Tropea : Comparative study of Euler/Euler and Euler/Lagrange approaches simulating evaporation in a gas-liquid flow; Numerical Methods in Fluids 59(8):873-906, doi:10.1002/fld.1844, Wiley 2009.