Free Surface 3D (FS3D)

Hier finden Sie Informationen über das hauseigene DNS Programm FS3D.
[Photo: K. Schulte (ITLR)]

The CFD program FS3D (Free Surface 3D) has been used at ITLR for more than 20 years and is constantly being further developed. Direct numerical simulation (DNS) is used to solve the incompressible Navier-Stokes equations. This means that no turbulence models are used, the occurring flow phenomena are captured by a correspondingly fine spatial and temporal resolution. To deal with the high computational effort involved, FS3D is parallelized using the MPI libraries and OpenMP, so that even complex problems can be investigated.

FS3D uses the Volume-of-Fluid (VOF) method to describe multiphase flow. The different phases are represented by additional field variables. In the case of a two phase flow, only one variable f is needed that can take per definition always values between 0 and 1. Based on this f distribution, the PLIC (piecewise linear interface calculation) method is used to reconstruct the actual interface.


  • Grouping phenomena in droplet streams
  • Droplet oscillation
  • Droplet wall, droplet-droplet and droplet-film interaction
  • Droplet impact on structured surface/wall
  • Droplet particle collision
  • Splashing
  • Heat and mass transfer in severely deformed drops
  • Jet breakup
  • Rising bubbles
  • Turbulent inflow generation
  • Droplet evaporation
  • Droplet freezing process
  • Multicomponent droplet
  • Raindrops

Selected Publications

  • M. Ibach, K. Schulte, V. Vaikuntanathan, A. Arad, D. Katoshevski, J. Greenberg, and B. Weigand, “Direct Numerical Simulations of Grouping Effects in Droplet Streams Using Different Boundary Conditions,” in ICLASS 2021, 15th Triennial International Conference on Liquid Atomization and Spray Systems, 2021, vol. Edinburgh, UK, 29 Aug.-2 Sept. 2021. doi:
  • J. Steigerwald, M. Ibach, J. Reutzsch, and B. Weigand, “Towards the Numerical Determination of the Splashing Threshold of Two-component Drop Film Interactions,” High Performance Computing in Science and Engineering ’20. Springer, 2020.
  • J. Reutzsch, G. Raja Kochanattu, M. Ibach, C. Kieffer-Roth, S. Tonini, G. Cossali, and B. Weigand, “Direct Numerical Simulations of Oscillating Liquid Droplets: a Method to Extract Shape Characteristics,” ILASS-Europe 2019, 29th Conference on Liquid Atomization and Spray Systems, vol. Paris, France, 2019.
  • Fest-Santini, S., Steigerwald, J., Santini, M., Cossali, G. E., & Weigand, B. (2021). Multiple drops impact onto a liquid film: Direct numerical simulation and experimental validation. Computers & Fluids214, 104761.
  • Ren, W., Reutzsch, J., & Weigand, B. (2020). Direct Numerical Simulation of Water Droplets in Turbulent Flow. Fluids5(3), 158.
  • Reutzsch, J., Kieffer-Roth, C., & Weigand, B. (2020). A consistent method for direct numerical simulation of droplet evaporation. Journal of Computational Physics413, 109455.
  • Loureiro, D. D., Reutzsch, J., Kronenburg, A., Weigand, B., & Vogiatzaki, K. (2020). Primary breakup regimes for cryogenic flash atomization. International Journal of Multiphase Flow132, 103405.
  • Baggio, M., & Weigand, B. (2019). Numerical simulation of a drop impact on a superhydrophobic surface with a wire. Physics of Fluids31(11), 112107.
  • Reitzle, M., Ruberto, S., Stierle, R., Gross, J., Janzen, T., & Weigand, B. (2019). Direct numerical simulation of sublimating ice particles. International Journal of Thermal Sciences145, 105953.
  • Ruberto, S., Reutzsch, J., Roth, N., & Weigand, B. (2017). A systematic experimental study on the evaporation rate of supercooled water droplets at subzero temperatures and varying relative humidity. Experiments in Fluids58(5), 55.
  • Ertl, M., & Weigand, B. (2017). Analysis methods for direct numerical simulations of primary breakup of shear-thinning liquid jets. Atomization and Sprays27(4).
  • Reitzle, M., Kieffer-Roth, C., Garcke, H., & Weigand, B. (2017). A volume-of-fluid method for three-dimensional hexagonal solidification processes. Journal of Computational Physics339, 356-369.
  • Eisenschmidt, K., Ertl, M., Gomaa, H., Kieffer-Roth, C., Meister, C., Rauschenberger, P., ... & Weigand, B. (2016). Direct numerical simulations for multiphase flows: An overview of the multiphase code FS3D. Applied Mathematics and Computation272, 508-517.
  • Rauschenberger, P., & Weigand, B. (2015). A Volume-of-Fluid method with interface reconstruction for ice growth in supercooled water. Journal of Computational Physics282, 98-112.
  • Rauschenberger, P., Criscione, A., Eisenschmidt, K., Kintea, D., Jakirlić, S., Tuković, Ž., ... & Tropea, C. (2013). Comparative assessment of Volume-of-Fluid and Level-Set methods by relevance to dendritic ice growth in supercooled water. Computers & fluids79, 44-52.
  • Zhu, C., Ertl, M., & Weigand, B. (2013). Numerical investigation on the primary breakup of an inelastic non-Newtonian liquid jet with inflow turbulence. Physics of Fluids25(8), 083102.
  • Schlottke, J., Straub, W., Beheng, K. D., Gomaa, H., & Weigand, B. (2010). Numerical investigation of collision-induced breakup of raindrops. Part I: Methodology and dependencies on collision energy and eccentricity. Journal of Atmospheric Sciences67(3), 557-575.
  • Sander, W., & Weigand, B. (2008). Direct numerical simulation and analysis of instability enhancing parameters in liquid sheets at moderate Reynolds numbers. Physics of Fluids20(5), 053301.
  • Schlottke, J., & Weigand, B. (2008). Direct numerical simulation of evaporating droplets. Journal of Computational Physics227(10), 5215-5237.
  • Gotaas, C., Havelka, P., Jakobsen, H. A., Svendsen, H. F., Hase, M., Roth, N., & Weigand, B. (2007). Effect of viscosity on droplet-droplet collision outcome: Experimental study and numerical comparison. Physics of fluids19(10), 102106.
  • Hase, M., & Weigand, B. (2004). Transient heat transfer of deforming droplets at high Reynolds numbers. International Journal of Numerical Methods for Heat & Fluid Flow.
  • Rieber, M., & Frohn, A. (1999). A numerical study on the mechanism of splashing. International Journal of Heat and Fluid Flow20(5), 455-461.


Contact Persons

This image shows Bernhard Weigand

Bernhard Weigand

Prof. Dr.-Ing. habil.


This image shows Jens von Wolfersdorf

Jens von Wolfersdorf

Prof. Dr.-Ing.

Deputy director

Susanne Stegmeier



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