Virtualization Infrastructure within the Controls Environment of the Light Sources at HZB

The advantages of visualization techniques and infrastructures with respect to configuration management, high availability and resource management have become obvious also for controls applications. Today a choice of powerful products are easy to use and support desirable functionality, performance, usability and maintainability at very matured levels. This paper presents the architecture of the virtual infrastructure and its relations to the hardware based counterpart as it has emerged for BESSY II and MLS controls within the past decade. Successful experiences as well as abandoned attempts and caveats on some intricate troubles are summarize

Wall turbulence at high friction Reynolds numbers

[EN] A new direct numerical simulation of a Poiseuille channel flow has been conducted for a friction Reynolds number of 10000, using the pseudospectral code LISO. The mean streamwise velocity presents a long logarithmic layer, extending from 400 to 2500 wall units, longer than it was thought. The maximum of the intensity of the streamwise velocity increases with the Reynolds number, as expected. Also, the elusive second maximum of this intensity has not appeared yet. In case it exists, its location will be around y(+) approximate to 120, for a friction Reynolds number extrapolated to approximately 13 500. The small differences in the near-wall gradient of this intensity for several Reynolds numbers are related to the scaling failure of the dissipation, confirming this hypothesis. The scaling of the turbulent budgets in the center of the channel is almost perfect above 1000 wall units. Finally, the peak of the pressure intensity grows with the Reynolds number and does not scale in wall units. If the pressure at the wall is modeled as an inverse quadratic power of Re-tau, then p(infinity)'(+) approximate to 4.7 at the limit of infinite Reynolds number.The authors gratefully acknowledge computing time provided by the Gauss Centre for Supercomputing e.V. on the GCS Supercomputer SuperMUC-NG at Leibniz Supercomputing Centre under Project No. pr92la, on the supercomputer Lichtenberg II at TU Darmstadt under Project No. project00072, and on the supercomputer CLAIX-2018 at RWTH-Aachen, Project No. bund0008. We are thankful to Mr. Monkewitz for providing us a copy of his model. S.K. and M.O. acknowledge funding by the German Research Foundation (DFG) through the Project No. OB96/39-1 and OB96/48-1. S.H. and F.A.A. were supported by Contract No. RTI2018-102256-B-I00 of MINECO/FEDER. F.A.A. is partially funded by GVA/FEDER Project No. ACIF2018. Finally, the authors thank Paul Hollmann for corrections with Latex.Hoyas, S.; Oberlack, M.; Alcántara-Ávila, F.; Kraheberger, SV.; Laux, J. (2022). Wall turbulence at high friction Reynolds numbers. Physical Review Fluids. 7(1):1-10. https://doi.org/10.1103/PhysRevFluids.7.0146021107

Turbulence Statistics of Arbitrary Moments of Wall-Bounded Shear Flows: A Symmetry Approach

[EN] The calculation of turbulence statistics is considered the key unsolved problem of fluid mechanics, i.e., precisely the computation of arbitrary statistical velocity moments from first principles alone. Using symmetry theory, we derive turbulent scaling laws for moments of arbitrary order in two regions of a turbulent channel flow. Besides the classical scaling symmetries of space and time, the key symmetries for the present work reflect the two well-known characteristics of turbulent flows: non-Gaussianity and intermittency. To validate the new scaling laws we made a new simulation at an unprecedented friction Reynolds number of 10 000, large enough to test the new scaling laws. Two key results appear as an application of symmetry theory, which allowed us to generate symmetry invariant solutions for arbitrary orders of moments for the underlying infinite set of moment equations. First, we show that in the sense of the generalization of the deficit law all moments of the streamwise velocity in the channel center follow a power-law scaling, with exponents depending on the first and second moments alone. Second, we show that the logarithmic law of the mean streamwise velocity in wall-bounded flows is indeed a valid solution of the moment equations, and further, all higher moments in this region follow a power law, where the scaling exponent of the second moment determines all higher moments. With this we give a first complete mathematical framework for all moments in the log region, which was first discovered about 100 years ago.The authors gratefully acknowledge computing time on the Gauss Centre for Supercomputing e.V. on the GCS Supercomputer SuperMUC-NG at Leibniz Supercomputing Centre under Project No. pr92la, on the supercomputer Lichtenberg II at TU Darmstadt under Project No. project00072, and on the supercomputer CLAIX-2018 at RWTH-Aachen under Project No. bund0008. S. V. K. gratefully acknowledges funding from projects OB96/39-1 and M. O. for partial funding from OB 96/48-1, both financed by the German Research Foundation (DFG) . S. H. and F. A.-A. were supported by Contract No. RTI2018-102256-B-I00 of Ministerio de Ciencia, innovacion y Universidades/FEDER. F. A.-A. is partially funded by GVA/FEDER project ACIF2018. Finally, the authors thank Paul Hollmann for help with the manuscript.Oberlack, M.; Hoyas, S.; Kraheberger, SV.; Alcántara-Ávila, F.; Laux, J. (2022). Turbulence Statistics of Arbitrary Moments of Wall-Bounded Shear Flows: A Symmetry Approach. Physical Review Letters. 128(2):1-6. https://doi.org/10.1103/PhysRevLett.128.02450216128

Conditions currently associated with erythema nodosum in Swiss children

A review was made of the 36 paediatric patients in whom the diagnosis of erythema nodosum had been established between 1977 and 1996 at the Department of Paediatrics, University of Bern, Switzerland. Infectious diseases were associated with erythema nodosum in 20 (including 10 streptococcal infections) and non-infectious inflammatory diseases in 8 patients. None of the 36 patients had tuberculosis or had been exposed to sulphonamides, phenytoin or hormonal contraceptives. There were eight patients in whom either the associated disease was not diagnosed, or there was no other disease. Conclusion Most cases of erythema nodosum are nowadays caused by non-mycobacterial infectious diseases or by non-infectious inflammatory disease

Effects of Magnetic Field on Josephson Current in SNS System

The effect of a magnetic field on Josephson current has been studied for a superconductor/normal-metal/superconductor (SNS) system, where N is a two-dimensional electron gas in a confining potential. It is found that the dependence of Josephson currents on the magnetic field are sensitive to the width of the normal metal. If the normal metal is wide and contains many channels (subbands), the current on a weak magnetic field shows a dependence similar to a Fraunhofer-pattern in SIS system and, as the field gets strong, it shows another type of oscillatory dependence on the field resulting from the Aharonov-Bohm interference between the edge states. As the number of channels decreases (i.e. normal metal gets narrower), however, the dependence in the region of the weak field deviates from a clear Fraunhofer pattern and the amplitude of the oscillatory dependence in the region of the strong field is reduced.Comment: 14 pages, 9 figure