Notes: [Auszug] reply The comment by Putterman et al. in essence addresses two questions: the role of water vapour inside bubbles that undergo single-bubble sonoluminescence, and the use of Rayleigh–Plesset dynamics to describe collapsing bubbles. Regarding the first point, water ...

Notes: Abstract: Solving the Navier-Stokes equation for incompressible fluids is greatly simplified by the solution of the vorticity equation. To accomplish this for three-dimensional flows requires vector potentials. These potentials are not only useful to take care of the incompressibility. Their modes are suitable also as test functions since the familiar Galerkin procedure does not work. The new method is checked by examples with known results and its relation to the classical approach with the stream function is clarified. The principle demonstration, however, concerns the transition to turbulence in plane shear flows. A simple layer of long rolls with axes parallel to the basic flow incites the transition.

Notes: This coming year, 2002, will already be the fifth year of publication for the European Physical Journal B, EPJ B. The journal is still influenced by the centennial tradition of its parent journals, Il Nuovo Cimento (section B), Journal de Physique and Zeitschrift für Physik B, which have formed the basis of the merger, EPJ B is rapidly expanding and has now managed to capture the interest of eleven European Physical Societies. We are happy to announce that in 2001 both the Polish Physical Society and the Roland Eötvös Physical Society from Hungary were included as part of our Scientific Advisory Committee. All information regarding the various sections of EPJ can be seen by accessing the Web address: http://www.eurphysj.org/ 2001 has been a healthy year for EPJ B with interesting physics, increasing support from the scientific community, an increase in the overall number of submissions, a growing readership and continuously improving performance of the editorial procedures. With high quality physics already published we continue to be a generalist physics journal focusing on specific themes of current interest. A special topic has also been emphasised in 2001 with a topical issue on Interdisciplinary Physics based on invited papers at the conference APFA-2 (Applications of Physics to Financial Analysis) in Liège, Belgium. This topic will be further emphasised again in 2002. Thanks to the competence of the Editorial Office and the efficiency of the publishers, we have reached a highly competitive publication time (with an average of 2.5 months between the acceptance and the publication of articles). As for the evaluation process, two or sometimes three referees are asked to advise the associate editors, therefore contributing to a thorough evaluation and often providing authors with valuable suggestions, with three quarters of the manuscripts accepted in less than four months (including revision time). This editorial is a good opportunity to thank very warmly all our colleagues, associate editors and their referees who have devoted time and effort to perform fair and constructive scientific evaluations. The quality of the journal has been recognised by the ISI impact factor since it has climbed from the twelfth up to the fifth rank from 1999 to 2000. EPJ B is now ranked as the first European-based journal in Condensed Matter Physics. Two new associate editors have joined the Editorial Board in 2001, M. Dacorogna (Interdisciplinary Physics) and F. Mila (Solid and Condensed Matter Physics), both of whom are located in Switzerland. More new associate editors are expected to join us in 2002. This will expand both the topical and geographical coverage of the journal. Let us remind you about the existence of the Rapid Notes which have been quite successful in EPJ B. These notes provide a means of publication of short papers, less than four printed pages, describing important advances, within three months of their reception by the Editorial Office. Authors, referees and the editorial office benefit from an improved inquiry service (IS) or manuscript management system (MMS) which allow on-line submissions, on-line response from referees as well as the follow up of the evaluation and production processes by the authors. Finally we are happy to announce that from now onwards the DOI referencing procedure will be used (http://www.doi.org) allowing a means of persistent electronic referencing to the on-line first version of the articles. All in all we have good reasons to be proud of this European-based journal with a world-wide distribution. All colleagues on the editorial staff can assure you that they will do all that is possible to spread high level scientific information and to please both its authors and readers. We invite you to remain with us, publish some of your best papers in EPJ B and read the journal on a regular basis. As always at the turn of the year, we wish you many outstanding results, many exciting discoveries and a Happy New Year. S. Grossmann, D. Jérome and A. Paoletti

Notes: Abstract: We interpret measurements of the Reynolds number dependence of the torque in Taylor-Couette flow by Lewis and Swinney [Phys. Rev. E 59, 5457 (1999)] and of the pressure drop in pipe flow by Smits and Zagarola [Phys. Fluids 10, 1045 (1998)] within the scaling theory of Grossmann and Lohse [J. Fluid Mech. 407, 27 (2000)], developed in the context of thermal convection. The main idea is to split the energy dissipation into contributions from a boundary layer and the turbulent bulk. This ansatz can account for the observed scaling in both cases if it is assumed that the internal wind velocity introduced through the rotational or pressure forcing is related to the external (imposed) velocity U, by with and for the Taylor-Couette (U inner cylinder velocity) and pipe flow (U mean flow velocity) case, respectively. In contrast to the Rayleigh-Bénard case the scaling exponents cannot (yet) be derived from the dynamical equations.