The Experts below are selected from a list of 21 Experts worldwide ranked by ideXlab platform
F. Durst - One of the best experts on this subject based on the ideXlab platform.
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Mean velocity and moments of turbulent velocity fluctuations in the wake of a model ship propulsor
Experiments in Fluids, 2007Co-Authors: J. P. Pêgo, H. Lienhart, F. DurstAbstract:Pod drives are modern outboard ship propulsion systems with a motor encapsulated in a watertight pod, whose shaft is connected directly to one or two propellers. The whole unit hangs from the stern of the ship and rotates azimuthally, thus providing thrust and steering without the need of a rudder. Force/momentum and phase-resolved laser Doppler anemometry (LDA) measurements were performed for in line co-rotating and contra-rotating propellers pod drive models. The measurements permitted to characterize these ship propulsion systems in terms of their hydrodynamic characteristics. The torque delivered to the propellers and the thrust of the system were measured for different operation conditions of the propellers. These measurements lead to the hydrodynamic optimization of the ship propulsion system. The parameters under focus revealed the influence of distance between propeller planes, propeller frequency of rotation ratio and type of propellers (co- or contra-rotating) on the overall efficiency of the system. Two of the ship propulsion systems under consideration were chosen, based on their hydrodynamic characteristics, for a detailed study of the swirling wake flow by means of laser Doppler anemometry. A two-component laser Doppler system was employed for the velocity measurements. A light barrier mounted on the axle of the rear propeller motor supplied a TTL signal to mark the beginning of each period, thus providing angle information for the LDA measurements. Measurements were conducted for four axial positions in the slipstream of the pod drive models. The results show that the wake of contra-rotating propeller is more homogeneous than when they co-rotate. In agreement with the results of the force/momentum measurements and with hypotheses put forward in the literature (see e.g. Poehls in Entwurfsgrundlagen für Schraubenpropeller, 1984 ; Schneekluth in Hydromechanik zum Schiffsentwurf, 1988 ; Breslin and Andersen in Hydrodynamics of ship propellers, 1996 ; Schneekluth and Bertram in Ship design for efficiency and economy, 1998 ), the co-rotating propellers model showed a much stronger swirl in the wake of the propulsor. The anisotropy of turbulence was analyzed using the anisotropy tensor introduced by Lumley and Newman (J Fluid Mech 82(1):161–178, 1977 ). The invariants of the anisotropy tensor of the wake flow were computed and were plotted in the Lumley–Newman-diagram. These measurements revealed that the anisotropy tensor in the wake of ship propellers is located near to the borders of the invariant map, showing a large degree of anisotropy. They will be presented and will be discussed with respect to applications of turbulence models to predict swirling flows.
Tu Hamburg-harburg - One of the best experts on this subject based on the ideXlab platform.
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Power Savings by Wake Equalizing Ducts
Ship Technology Research, 2005Co-Authors: Tu Hamburg-harburgAbstract:The commercial RANSE code Comet is employed to investigate in detail the flow around a so-called wake-equalizing duct proposed by Schneekluth. The numerical analyse shows that the duct is not equalizing the wake at all, and its effect is marginal to negative at full scale.
Thorsten Bothe - One of the best experts on this subject based on the ideXlab platform.
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stephen kings das madchen Schneekluth verlag eine rhetorische lekture des schutzumschlags
Belphégor. Littérature populaire et culture médiatique, 2015Co-Authors: Thorsten BotheAbstract:“The book as an object is comfortingly substantial in its content and its material presence. At a time when so much information is dispersed in virtual form, it is especially important to examine the book as a distinctive object reflecting a marriage of authors’ words and designers’ vision.” In Bibliotheken und Archiven findet man ihn selten – zumindest nicht am Stuck. Wenn doch, dann an Sonderstandorten, in Kartons und auch nur dann, wenn genug Platz zu deren Aufbewahrung vorhanden ist. Selt...
J. P. Pêgo - One of the best experts on this subject based on the ideXlab platform.
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Mean velocity and moments of turbulent velocity fluctuations in the wake of a model ship propulsor
Experiments in Fluids, 2007Co-Authors: J. P. Pêgo, H. Lienhart, F. DurstAbstract:Pod drives are modern outboard ship propulsion systems with a motor encapsulated in a watertight pod, whose shaft is connected directly to one or two propellers. The whole unit hangs from the stern of the ship and rotates azimuthally, thus providing thrust and steering without the need of a rudder. Force/momentum and phase-resolved laser Doppler anemometry (LDA) measurements were performed for in line co-rotating and contra-rotating propellers pod drive models. The measurements permitted to characterize these ship propulsion systems in terms of their hydrodynamic characteristics. The torque delivered to the propellers and the thrust of the system were measured for different operation conditions of the propellers. These measurements lead to the hydrodynamic optimization of the ship propulsion system. The parameters under focus revealed the influence of distance between propeller planes, propeller frequency of rotation ratio and type of propellers (co- or contra-rotating) on the overall efficiency of the system. Two of the ship propulsion systems under consideration were chosen, based on their hydrodynamic characteristics, for a detailed study of the swirling wake flow by means of laser Doppler anemometry. A two-component laser Doppler system was employed for the velocity measurements. A light barrier mounted on the axle of the rear propeller motor supplied a TTL signal to mark the beginning of each period, thus providing angle information for the LDA measurements. Measurements were conducted for four axial positions in the slipstream of the pod drive models. The results show that the wake of contra-rotating propeller is more homogeneous than when they co-rotate. In agreement with the results of the force/momentum measurements and with hypotheses put forward in the literature (see e.g. Poehls in Entwurfsgrundlagen für Schraubenpropeller, 1984 ; Schneekluth in Hydromechanik zum Schiffsentwurf, 1988 ; Breslin and Andersen in Hydrodynamics of ship propellers, 1996 ; Schneekluth and Bertram in Ship design for efficiency and economy, 1998 ), the co-rotating propellers model showed a much stronger swirl in the wake of the propulsor. The anisotropy of turbulence was analyzed using the anisotropy tensor introduced by Lumley and Newman (J Fluid Mech 82(1):161–178, 1977 ). The invariants of the anisotropy tensor of the wake flow were computed and were plotted in the Lumley–Newman-diagram. These measurements revealed that the anisotropy tensor in the wake of ship propellers is located near to the borders of the invariant map, showing a large degree of anisotropy. They will be presented and will be discussed with respect to applications of turbulence models to predict swirling flows.
Kafka, Ioanna N. - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the hydrodynamic behavior of Schneekluth ducts on a ship model
2013Co-Authors: Καυκά, Ιωάννα Ν., Kafka, Ioanna N.Abstract:252 σ.Σκοπός της παρουσας διπλωματικης εργασίας είναι η μελέτη και ανάλυση μέσω πειραματικών μετρήσεων της υδροδυναμικής συμπεριφοράς δακτυλίων Schneekluth προσαρμοσμένων σε πρότυπο πλοίου.Για την διεξαγωγή συμπερασμάτων γίνεται σύγκριση των αποτελεσμάτων που αφορούν την ισχύ που αποδίδεται στην έλικα και τον βαθμό απόδοσης της προωστήριας εγκατάστασης του πλοίου πρίν και μετα την τοποθέτηση των ημιδακτυλίων.The purpose of the current individual project is the analysis and the study of the hydrodynamic behavior of Schneekluth Ducts on a ship model. In order to reach a conclusion a comparison method between the delivered power of the propeler and tha propulsive coefficient was used before and after the installation of the ducts.Ιωάννα Ν. Καυκ