The paper is concerned with experimental and numerical investigations of the turbulent flow over dimpled surfaces. Shallow dimples distributed regularly over the wall of a plane channel with large aspect ratio are used to study their effect on the skin-friction drag. The resulting pressure drop in the channel was measured for smooth and dimpled walls. In addition to these investigations on internal flows, an external flow study was performed and boundary-layer profiles were measured using a Pitot-tube rake. Complementary to the measurements, direct numerical simulations for the internal flow configuration with and without dimples were carried out for two different grid resolutions and analyzed in detail. The objective was to clarify whether or not dimples cause reduction of the skin-friction drag.

The paper is concerned with an experimental and numerical investigation of the turbulent flow over dimpled surfaces. Shallow dimples distributed regularly over the wall of a plane channel with large aspect ratio are used to study their effect on the friction drag. The resulting pressure drop in the channel was measured for smooth and dimpled walls. In addition to these investigations on internal flows, an external flow study was performed and boundary-layer profiles were measured using a Pitot-tube rake. Complementary to the measurements, direct numerical simulations for the internal flow configuration with and without dimples were carried out for two different grid resolutions and analyzed in detail. The objective was to clarify whether or not dimples cause reduction of the skin-friction drag. © 2008 Elsevier Inc. All rights reserved.

The research unit FOR 493 tackles the challenging task of fluid-structure interaction (FSI). On the one hand, the objective is to provide reliable experimental reference data for all groups which are developing numerical methodologies to predict such coupled FSI problems. Since measurements on fluid-structure interaction setups using welldefined boundary and operating conditions are rare, the present Particle Image Velocimetry and excitation measurements for a swiveling flat plate support to fill a gap by providing phase-resolved data of this useful test case. On the other hand, the objective is to develop numerical methods for coupled FSI investigations which involve turbulent flows. Thus, an especially designed coupling scheme to be used in combination with the large-eddy simulation technique was set up and applied to study the flow around the hinged flat plate and the development of self-excited periodic processes with rotary oscillation of the flat plate. © 2010 Springer-Verlag Berlin Heidelberg.