Hof, Björn, Prof. Dr.
- Study of Physics at the Universities of Marburg and Manchester
- 1997 MSc in Physics, University of Manchester
- 2001 PhD at the University of Manchester
- 2000-2003 Research Associate, University of Manchester
- 2003-2005 Research Associate, Delft University of Technology
- 2005-2007 RCUK Fellow / Lecturer in Physics at the University of Manchester
- 2007-present Max Planck Research Group Leader, MPI for Dynamics and Self-Organization, Göttingen
- since 2013 Professor at the Institute of Science and Technology Austria
Major Research Interests
The main aim of our work is to understand how complexity and disorder arises in fluid flows.
While in some of the systems that we study complexity arises in well defined steps (bifurcation sequences), in other systems the motion suddenly and unpredictably jumps from ordered to completely disordered (i.e. turbulent) motion. In particular to understand the latter systems offers a great challenge and new theoretical approaches are required to understand these problems. In combined experimental and numerical studies we were able to show that the localized patches of turbulence occurring at low Reynolds numbers are transient and that the correct phase space representation is that of a chaotic repeller. However turbulence also has a tendency to spread and by an in depth study of these mechanisms we most recently succeeded in resolving a 125 year long quest for the critical point in pipe flow, marking the onset of sustained turbulence. Current investigations also include numerical and experimental studies of laterally extended systems (such as Couette, Poiseuille and Taylor-Couette flows). One of our main aims is to test and establish universal aspects of the transition scenarios. Other studies in my group are concerned with the flow structures underlying turbulent motion. We are here in particular interested in the relevance of unstable solutions of the Navier Stokes equations and their potential role as building blocks of the turbulent dynamics. Very recently we for the first time succeeded in quantify and confirm the role of such structures by converging a flow state observed in the experiment to an exact travelling wave solution. Ultimately we hope that such concepts will provide a clearer understanding of how turbulence is organised and help to develop low dimensional models of turbulence. Another area of our research is devoted to turbulence control. By exploiting insights into the turbulence sustaining mechanism we could for the first time demonstrate that intermittently turbulent flows can be fully relaminarized and that control costs are low. In addition we have now developed more sophisticated methods which allow us to also relaminarize fully turbulent flows at much higher Reynolds numbers (patent application WO PCT/EP2010/067959). More recently we have also extended our work to more complex situations where multiple self organizing processes compete. These studies include polymer flows, phase separation as well as the formation of biofilms in turbulent flows and locomotion of plankton larvae.
Homepage Department/Research Group
Selected Recent Publications
- de Lozar, A., Mellibovsky, F., Avila, M. & Hof, B. (2012) Edge state in pipe experiments. Phys Rev. Lett. 108, 214502
- K. Avila, D.Moxey, A. de Lozar, M.Avila, D. Barkley & B.Hof (2011) The onset of turbulence in pipe flow. Science 333, 192
- B.Hof, A. de Lozar, M.Avila, X.Tu, T.M. Schneider (2010) Eliminating turbulence in spatially intermittent flows. Science 327, 1491
- Avila, M., Willis, A. & Hof, B. (2010) On the transient nature of localized pipe flow turbulence. J. Fluid. Mech., 127-136.
- Hof, B., deLozar, A., Kuik, D.J. & Westerweel, J. (2008) Repeller or attractor? Selecting the dynamical model for the onset of turbulence in pipe flow. Phys. Rev. Lett. 101, 214501
- B. Hof, J. Westerweel, T.M. Schneider & B. Eckhardt (2006) Finite Lifetime of Turbulence in Pipe Flow. Nature 443, 05089, pp 59-62
- B. Hof, C.W.H. van Doorne, J. Westerweel, F.T.M. Nieuwstadt, H. Faisst, B. Eckhardt, H.Wedin, R.Kerswell, F. Waleffe (2004) Experimental observation of nonlinear travelling waves in turbulent pipe flow. Science 305, Issue90, pp 1594-1598
- B.Hof, A.Juel & T.Mullin (2003) Scaling of the turbulence transition threshold in a pipe. Phys. Rev. Lett. 91, 244502