Publications

Peer reviewed journal papers

Wasserfall, J., Figueiredo, P., Kneer, R., Rohlfs, W., Pischke, P.: Coalescence-induced droplet jumping on superhydrophobic surfaces: Effects of droplet mismatch. Physical Review Fluids, 2, 123601, 2017.

Rietz, M., Scheid, B., Gallaire, F., Kofman, N., Kneer, R., Rohlfs, W.: Dynamics of falling films on the outside of a vertical rotating cylinder: waves, rivulets and dripping transitions. J. of Fluid Mechanics, 832, 180-211. (Providing front cover image of JFM Volume 832)

Haustein, H.D., Harnik, R. S., Rohlfs, W.: A simple hydrodynamic model of a laminar free-surface jet in horizontal or vertical flight. Physics of Fluids, 29, 081205, 2017.

Jörg, J., Taraborrelli, S., Sarriegui, G., Kneer, R., De Doncker, R., Rohlfs, W.: Direct Single Impinging Jet Cooling of a MOSFET Power Electronic Module. IEEE Transactions on Power Electronic, 99, 2017.

Rohlfs, W., Pischke, P., Scheid, B.: Hydrodynamic waves in films flowing under an inclined plane, Physical Review Fluids, 2, 4, 044003, 2017.

Bieber, M., Kneer, R., Rohlfs, W.: Self-similarity of heat transfer characteristics in laminar submerged and free-surface slot jet impingement, Int. J. of Heat and Mass Transfer, 104, 1341-1352, 2017.

Rohlfs, W., Thiel, G. P., Lienhard V, J.H.: Modeling reverse osmosis element design using superposition and an analogy to convective heat transfer, J. of Membrane Science, forthcoming, 2016.

Scheid, B., Kofman, N., Rohlfs, W.: Critical inclination for Absolute/Convective instability transition in inverted falling films, Physics of Fluids, forthcoming, 2016.

Rohlfs, W., Lienhard V, J.H.: Entrance length effects on Graetz number scaling in laminar duct flows with periodic obstructions: Transport number correlations for spacer-filled membrane channel flows, Int. J. of Heat and Mass Transfer, 97, 842-852, 2016.

Sabelberg, E., Cardenas, M., Kneer, R., Rohlfs, W.: Design, development, and validation of concepts for generating passive pulsation in cooling nozzles. Case Studies in Thermal Engineering, forthcoming, 2016.

Gronarz, T., Frekers, Y., Kneer, R., Rohlfs, W.: The influence of subsurface temperature measure-ments on the determination of transient wall-side boundary conditions: An analytical tool, Heat Transfer Engineering, forthcoming, 2016.

Seel, K., Reddemann, M., Verbaere, V. Mathieu. F., Cárdenas, M., Rohlfs, W., Haustein, H. D., Kneer, R.: A spin coating device for the investigation of spray-film interactions under engine relevant conditions. Atomization and Sprays, forthcoming, 2016.

Rohlfs, W., Scheid, B.: Phase diagram for the onset of circulating waves and flow reversal in inclined falling films, J. of Fluid Mechanics, 763, 322-351, 2015.

Rietz, M., Rohlfs, W., Kneer, R., Scheid, B.: Experimental investigation of thermal structures in regular three-dimensional falling films, European Physics J. Special Topic, 224, 355-368, 2015.

Gronarz, T., Frekers, Y., Kneer, R., Rohlfs, W.; The influence of subsurface temperature measure-ments on the determination of transient wall-side boundary conditions: An analytical tool, Heat Transfer Engineering, forthcoming, 2015.

Rohlfs, W., Ehrenpreis, C., Haustein, H., Kneer, R.: Influence of viscous flow relaxation time on self-similarity in free-surface jet impingement, Int. J. of Heat and Mass Transfer, 78, 435-446, 2014.

Rohlfs W., Madlener R.: Optimal Investment Strategies in Power Generation Assets: The Role of Technological Choice and Existing Portfolios in the Deployment of Low-Carbon Technologies. Int. J. Greenhouse Gas Control, 28, 114-125, 2014.

Rohlfs, W., Binz, M., Kneer, R.: On the stabilizing effect of a liquid film on a cylindrical core by oscillatory motions. Physics of Fluids, 26, 022101, 2014.

Binz, M., Rohlfs, W., Kneer, R.: Direct numerical simulations of a thin liquid film coating an axially oscillating cylindrical surface. Fluid Dynamics Research, 46, 041402, 2014.

Dietze, G. F., Rohlfs, W., Nährich, K., Kneer, R., Scheid, B.: Three-dimensional flow structures in laminar falling liquid films. J. of Fluid Mechanics, 743, 75-123, 2014.

Rohlfs, W., Madlener, R.: Multi-Commodity Real Options Analysis of Power Plant Investments: Discounting Endogenous Risk Structures. Energy Systems J., 5 (3), 423-447, 2014.

Tsvelodub, O., Rohlfs, W., Kneer, R.: Modeling of wave modes on a vertical film of a viscous ferromagnetic fluid flowing down a cylindrical electric conductor, Physics of Fluids, 25, 092101, 2013.

Rohlfs, W., Madlener, R.: Assessment of Clean-Coal Strategies: The Questionable Merits of Carbon Capture-Readiness Energy, 52, 27-36, 2013.

Rohlfs, W., Dietze, G., F., Haustein, D., Kneer, R.: Experimental investigation of 3-dimensional wavy liquid films under the coupled influence of thermo-capillary and electrostatic forces European Physics J. Special Topic, 219, 111-119, 2013.

Rohlfs, W., Haustein, H., Garbrecht, O., Kneer, R.: Insights into the local heat transfer of a submerged impinging jet: Influence of local flow acceleration and vortex-wall interaction Int. J. of Heat and Mass Transfer, 55, 7728-7736, 2012.

Haustein, H., Tebrügge, G., Rohlfs, W., Kneer, R.: Local heat transfer coefficient measurement through a visibly-transparent heater under jet-impingement cooling Int. J. of Heat and Mass Transfer, 55, 23-24, 6410-6424, 2012.

Haustein, H., Rohlfs, W., Al-Sibai, F., Kneer, R.: Evaluation of the Sensitivity and Response of IR Thermography from a Transparent Heater in the Case of Liquid Jet Impingement J. of Physics: Conference Series, 395, 012083, 2012.

Rohlfs, W., Dietze, Georg, F., Haustein, D., Kneer, R.: Two-phase electrohydrodynamic simulations using a volume-of-fluid approach: A comment. J. of Computational Physics, 231, 4454-4463, 2012.

Rohlfs, W., Dietze, G. F., Haustein, H. D., Tsvelodub, O., Kneer, R.: Experimental investigation of 3-dimensional wavy liquid films under the influence of electrostatic forces. Experiments in Fluids, 53 (4), 1045-1056, 2012.

Rohlfs, W., Madlener, R.: Valuation of CCS-ready coal-fired power plants: a multi-dimensional real options approach. Energy Systems J., 2 (3-4), 243-261, 2011.

Papers published in proceedings of professional conferences

Van Buren, S.H., Hertle, E., Figueiredo, P., Kneer, R., Rohlfs, W.: Modeling the defrost process in complex geometries – Part 1: Development of a one-dimensional defrost model. Proceedings of the 1st International Conference on Advances in Energy Systems and Environmental Engineering (ASEE17), 2nd-5th July 2017, Wroclaw, Poland.

Hertle, E., Van Buren, S.H., Figueiredo, P., Kneer, R., Rohlfs, W.: Modeling the defrost process in complex geometries – Part 2: Wall-function based coupling to a multi-region CFD solver. Proceedings of the 1st International Conference on Advances in Energy Systems and Environmental Engineering (ASEE17), 2nd-5th July 2017, Wroclaw, Poland.

Jörg, J., Taraborrelli, S., Sabelberg, E., Kneer, R., De Doncker, R., Rohlfs, W.: Hot Spot Removal in Power Electronics by means of Direct Liquid Jet Cooling. Proceedings of IEEE ITHERM 2017 (The Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems), May 30th– June 02nd, 2017.

Rohlfs, W., Bieber, M., Ehrenpreis, C., Jörg, J., Sabelberg, E., Kneer, R.: Flow structures and heat transfer characteristics in arrays of submerged laminar impinging jets. In Proc. Appl. Math. Mech. 16, 2016.

Lienhard V, J. H., Thiel, G. P., Rohlfs, W.: Making desalination an energy efficient alternative. Proceedings Proceedings of the First Pacific Rim Thermal Engineering Conference, PRTEC, March 13th-17th, 2016, Hawaii’s Big Island, USA.

Hundhausen A., Rietz, M., Allelein, H.-J., Belt, A., Garbrecht, O., Kneer, R., Rohlfs, W.: Experimental assessment of single lens volumetric PIV with a commercial light field camera, Proceedings of the 11th International Symposium on Particle Image Velocimetry, PIV15, September 14th -16th , 2015, Santa Barbara, California, USA.

Rohlfs W., Jörg, J., Ehrenpreis, C., Rietz, M., Haustein, H., Kneer, R.: Flow Structures and heat transfer in submerged laminar jet impingement, TFESC-12816, Proceedings of the 1st Thermal and Fluids Engineering Summer Conference, TFESC-1, August 9th-12th, 2015, New York City, USA.

Rohlfs, W., Kneer, R., Scheid, B..: Influence of gravity and electrostatic surface forces on the onset of rolling waves and flow reversal in falling liquid films, Proceedings of the 7th International Berlin Workshop – IBW7 on Transport Phenomena with Moving Boundaries, October 30th-31st, 2014, Berlin, Germany, Published VDI Fortschritt-Bericht VDI Reihe 3, Verfahrenstechnik 947, Düsseldorf VDI-Verlag, 2015.

Rietz, M., Garbrecht, O., Rohlfs, W., Kneer, R.: Combined Three-Dimensional Flow- and Temperature Field Measurements Using Digital Light Field Photography, IHTC15-8605, Proceedings of the 15th International Heat Transfer Conference, IHTC-15, August 10th -15th , 2014, Kyoto, Japan.

Rohlfs, W., Ehrenpreis. C., Haustein, H.D., Garbrecht, O., Kneer, R.: Influence of local flow acceleration on the heat transfer of submerged and free-surface jet impingement, IHTC15-8378, Proceedings of the 15th International Heat Transfer Conference, IHTC-15, August 10th -15th , 2014, Kyoto, Japan.

Kneer, R., Haustein, H.D., Ehrenpreis, C., Rohlfs, W.: Flow Structures and Heat Transfer in Submerged and Free Laminar Jets, IHTC15-KN11, Proceedings of the 15th International Heat Transfer Conference, IHTC-15, August 10th -15th , 2014, Kyoto, Japan.

Haustein, H.D., Jörg, J., Rohlfs, W., Al-Sibai, F., Kneer, R.: Influence of Micro-scale Aspects and Jet-to-jet Interaction on Free-surface Liquid Jet Impingement for Micro-jet Array Cooling, Proceedings of the IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems – ITHERM 2014, May 27th-30th, Orlando, FL, USA, 2014.

Haustein, H.D., Rohlfs, W., Al-Sibai, F., Kneer, R.: Development of Heat Transfer in a Two-Dimensional Wavy Falling Film of Water and its Influence on Wave Stability, Proceedings of the ASME Summer Heat Transfer Conference, Paper No. HT2013-17453 July 14th-19th, Minneapolis, MN, USA, 2013.

Rohlfs, W., Madlener, R.: Investment decisions under uncertainty: CCS competing with green energy technologies, Energy Procedia 37, 7029-7038, 2013 Proceedings of the 11th International Conference on Greenhouse Gas Technology – GHGT-11, November 18th-22nd, Kyoto, Japan.

Rohlfs, W., Haustein, H. D., Dietze, G. F., Kneer, R.: Experimental and numerical investigation of falling liquid films influenced by the presence of electric fields, Proceedings of the 6th International Berlin Workshop – IB63 on Transport Phenomena with Moving Boundaries, November 24th-25th, 2011, Berlin, Germany, Published VDI Fortschritts-Bericht VDI Reihe 3, Verfahrenstechnik 929, Düsseldorf VDI-Verlag, 2012.

Hallo, hier ein Link zu heatquiz

HeatQuiz Energy balances

 

Neueste Beiträge

DFG funds new research on falling liquid films

First successful application for a DFG project on dripping in falling liquid films!!

Falling liquid films are of technical relevance in a multitude of applications in energy and process engineering. The relevant literature offers a comprehensive overview of film evolution and film transfer properties on inclined or vertical walls and differing surface geometries. Experimental and numerical data of films underneath an inclined plane are very scarce, despite their importance in e.g. coating problems or structured packings
in chemical engineering. In these applications, the prevention of dripping to ensure homogeneous coatings or the promotion of dripping to increase liquid/gas interface areas is of high interest. Due to the non-linear character of dripping from films beneath surfaces, an analytical approach to the problem is difficult and correlations for the onset of dripping and a quantification of dripping mass flows are not available at present. Within the proposed project, the dripping regime in films flowing beneath basic surface geometries is analyzed through fully resolved numerical simulation, low-dimensional modeling and experimental investigations. The aim is to provide physically motivated correlations for the onset of dripping and to quantify dripping mass flows and specific surface areas to enable a targeted design of respective processes.

  1. TV contribution: What is the reason for noise in water boiling? Kommentare deaktiviert für TV contribution: What is the reason for noise in water boiling?
  2. The HeatQuiz development continues (Fellowship for Digital Teaching) Kommentare deaktiviert für The HeatQuiz development continues (Fellowship for Digital Teaching)
  3. Current research covers the title page of JFM Kommentare deaktiviert für Current research covers the title page of JFM