Now showing 1 - 6 of 6
  • Publication
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  • Publication
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    Modeling of wind gusts for large-eddy simulations related to fluid-structure interactions
    (Springer, 2019) ; ;
    Perali, Paolo
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    Grollmann, Kai Michael
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    Salvetti, Maria Vittoria
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    Armenio, Vincenzo
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    Fröhlich, Jochen
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    Geurts, Bernard J.
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    Kuerten, Hans
    © Springer Nature Switzerland AG 2019. The dimensioning of lightweight structures under wind loads strongly depends on realistic flow conditions. Two different setups have to be distinguished. For a long-term analysis such as dynamic fatigue, temporally and spatially correlated velocity distributions are required as inflow conditions for a large-eddy simulation (LES) to mimic a realistic physical setup (Wood et al, Flow Turbul Combust 97(1):79–119, 2016, [9]).
  • Publication
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    Complementary Experimental-Numerical Investigation of the Flow past a Rigid and a Flexible Hemisphere in Turbulent Flow : Part II: Numerical Simulations
    (Deutsche Gesellschaft für Laser-Anemometrie GALA e.V., 2016) ; ; ;
    Egbers, Christoph
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    Ruck, Bodo
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    Leder, Alfred
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    Dopheide, Dietrich
  • Publication
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    A new turbulent three-dimensional FSI benchmark FSI-PFS-3A: Definition and measurements
    (International Center for Numerical Methods in Engineering, 2013-05)
    Kalmbach, Andreas
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    In the last decade, the demand for the prediction of complex multi-physics prob-lems such as fluid-structure interaction (FSI) has strongly increased. For the development and improvement of appropriate numerical tools several test case swere designed in order to vali-date the numerical res ults based on experimental reference data [4, 12, 13, 8, 9, 10 ]. Since FSI problems often occur inturbulent flows also in the experiments similar conditions have to be provided. Inthetest - case FSI - PfS- 1a [7] presented in the first contribution to this session, acylinder is used with anattached flexible rubber plate. Theresulting FSI problem is nearly two - dimensionalregarding the phase -averaged flow and thes tructure deformations. Theac - tualtestcase FSI - PfS -3a is the reasonable further development step of this two - -dimensional flow, Which now alsoleads to a significant three - dimensional structure deformation. Thecy linder is replaced by a truncated cone .Similar to FSI - PfS - 1a [7] arubber plate is attachedat the backside. This geometrical setup is exposed to aconstant flowat Re = 32 ,000 which hisin the subcritical regime. Dueto the linearly increasing diameter of the cone the alternating eddies in the wake even become larger resulting incorre - spondingly increasing structural displacements. Owingt o thes echallenging flow and structure effects, this benchmark will be the next step for validating FSI predictions for real applications. The experiments are performed in a water channel with clearly defined and controllable bound - ary and operating conditions. Formeasuring the flowa two - dimensional mono - particle - image velocimetry (PIV) system isapplied. In order to characterize the three - dimensional behaviorof the flow, phase - averaged PIV measurements are performed at three different planes. The structural deformations are measured along a line on the structure surface with atime - resolved laser distance sensor. The resulting FSI problem shows a quasi - periodic deformation behavior so that a phase averaging of the results is reasonable. Byphase - averaging turbulent fluctua-tions are averaged out and thus a comparison with corresponding numerical simulations basedon LES [3] and RANS [12, 13] approaches is possible.
  • Publication
    Metadata only
    Fluid-structure interaction in turbulent flows: LES predictions and PIV measurements
    (2012-12) ; ;
    Kalmbach, Andreas
    This contribution presents a complementary numerical/experimental investigation on a new fluid-structure interaction (FSI) test case denoted FSI-PfS-1. In comparison to previously suggested FSI benchmark cases (see Gomes and Lienhart (2006, 2010)) the present configuration is less challenging from the computational point of view. The reasons are versatile: Owing to a fixed cylindrical front body the mechanical system has less degrees of freedom. Furthermore, the swiveling structure is consisting of a unique material without an additional rear weight. Finally, the thickness of the flexible structure is 50 times larger than the very thin structure used in previous investigations. The structural model was installed in a water tunnel and operated in the subcritical turbulent regime at a Reynolds number of Re = 3 104. Based on optical measuring techniques the phase-averaged flow field as well as the deformation of the structure were experimentally determined. Additionally, the FSI test case was predicted by a partitioned semi-implicit predictor-corrector coupling scheme applying the large-eddy simulation technique. The contribution presents a first comparison concerning the phase-resolved flow field and the structure deformation. The swiveling motion of the flexible structure found in the experiment is predicted in reasonable agreement. Finally, an outlook is given about all issues of the benchmark case which need further evaluations and improvements.