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Aerodynamische Modelle

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Erkannte Entitäten
Sprachtranskript
Reitwein close to Germany's border with Poland. Military manoeuvres here badly damaged groynes in the River Oder. Repairing the groynes had to take account of the needs of shipping and of flood and nature protection. A range of variants were tried out in an aerodynamic
model in the Federal Waterways Engineering and Research Institute in Karlsruhe.
Instead of water currents, aerodynamic models work with air currents. The model is based
on a detailed digital model of the terrain. The scale of length is 1:350. Three kilometres in reality are represented by 8.5 metres in the model. The terrain data are gathered by means of laser scan flights and river bed data by underwater soundings. Unsuitable solutions can already be ruled out with the erosion method by making the current close to the bottom visible. For this, a mixture of petroleum and talcum powder is sprayed on the surface. The model
is then covered with a
glass plate. The measuring gantry spans the model at about chest-height. A sliding cradle unit on the aluminium frame carries the measuring instruments. The system permits very precise, triaxial measurement.
The underside of the glass approximates to the water surface.
Where the air current is strong, the talcum particles collect along the line of flow, resulting in bottom streamlines.
Botton streamlines near a longitudinal dam, intended to replace the damaged groynes. White areas show that the current is weak - for instance, in the groyne fields. The gasket is removed
from a hole drilled in
the glass cover so that a measuring probe can be inserted in the current. It measures the flow velocity using hot wire velocimetry. The probes
are inserted at intervals of 3 centimetres, corresponding to every 10.5 metres in reality. Measurements
are taken from the river bed to the surface. Flow direction and velocity measured in several cross-sections result in 3-dimensional images. This cross-section of the Oder shows faster velocities in yellow and green, and slower currents in pale and dark blue. To the left behind the training wall, and on the right in the groyne field, the velocity is much slower than in the main current. For this measurement, static pressure probes with pressure transducers are inserted into the model.
Pressure measurements reveal the pressure drop in the model. This
serves as an indicator of the water level gradient.
A mist made up of water and alcohol is drawn into the model. The mist is
used to make the flow visible and to measure the
flow direction and velocity. Slowed down 20 times, the film reveals eddies in the area of the damaged groynes, which peel away from the river bank and the remains of the groynes. They couldn't be seen with the naked eye because it takes only a quarter-of-a-second for the air to flow through the 8.5 metre length of the model. Eddies in a groyne field detaching from the flow over and around the groyne. A laser device is used to measure the velocity. The light is split into two beams, which are then focussed by a lens. The intercept point of the two beams is the measuring point. The measured velocities enable a colour-coded animated chart to be produced, showing the air flow velocities at water level. Numerical particles are added for a computer analysis of of the flow. These two pipes draw the mist through the model at speeds of up to 30 metres a second.
The flow rate is recorded by a standard volume flow meter. It can be varied via the suction fan controls. The tests reveal that navigation conditions will best be improved by reconstructing the groynes. With due consideration for ecological aspects, a segmented longitudinal dam with protruding groynes could also be recommended.
Schiff
Nassdampfturbine
Modellbauer
Modell <Gießerei>
Flugverhalten
Modellbauer
Bett
Erdöl- und Erdgastechnik
Modell <Gießerei>
Brückenkran
Photographische Platte
Kraftfahrzeug
Nassdampfturbine
Glasherstellung
Mikroskopie
Locher
Zylinderkopfdichtung
Eisendraht
Glasherstellung
Einbandmaterial
Fahrgeschwindigkeit
Förderleistung
Personenzuglokomotive
Verdichter
Bett
Modellbauer
Fahrgeschwindigkeit
Förderleistung
Computeranimation
Nassdampfturbine
Modellbauer
Radialgebläse
Hydraulikleitung
Modellbauer
Fahrgeschwindigkeit
Förderleistung

Metadaten

Formale Metadaten

Titel Aerodynamische Modelle
Alternativer Titel Aerodynamic Models
Autor Schledding, Thomas
Mitwirkende Petra Faulhaber (wissenschaftliche Betreuung)
Bernd Hentschel (wissenschaftliche Betreuung)
Kuno Lechner(Kamera)
Uwe Fanelli (Kamera)
Thomas Gerstenberg (Ton)
Abbas Yousefpour (Schnitt)
Lizenz CC-Namensnennung 4.0 International:
Sie dürfen das Werk bzw. den Inhalt zu jedem legalen Zweck nutzen, verändern und in unveränderter oder veränderter Form vervielfältigen, verbreiten und öffentlich zugänglich machen, sofern Sie den Namen des Autors/Rechteinhabers in der von ihm festgelegten Weise nennen.
DOI 10.5446/14866
IWF-Signatur C 13224
Herausgeber Bundesanstalt für Wasserbau (BAW)
Erscheinungsjahr 2010
Sprache Englisch
Produzent IWF
Produktionsjahr 2008

Technische Metadaten

IWF-Filmdaten Video-Clip ; F, 5 min

Inhaltliche Metadaten

Fachgebiet Technik
Abstract Anstelle von Wassermodellen baut die BAW auch platzsparende und kostengünstige Luftmodelle. Die Wasserströmung in der Natur wird dabei durch Luftströmung in einem Unterdrucksystem simuliert. Das Erosionsverfahren macht die Strömung an der Sohle mit einem Talkum-Petroleum-Gemisch schnell und deutlich sichtbar. Mit der Hitzdraht-Anemometrie wird die Fließgeschwindigkeit der Luft gemessen. Druckmessungen liefern das Druckgefälle im Modell. Dieses dient als Kriterium für das Wasserspiegelgefälle. Die Fließgeschwindigkeit wird auch mit einem Laserdopplermessverfahren bestimmt. Die Ergebnisse fließen in Computermodelle ein. Der Einsatz dieser Modelltechnik wird an einem wasserbaulichen Problem an der Oder bei Reitwein demonstriert.
The BAW works with space saving and cost efficient aerodynamic models instead of water models. The natural water flow is simulated by an air flow in a negative pressure system. The erosion procedure uses a talcum-petroleum mixture to make the flow on the river bed quickly and clearly visible. The flow velocity of the air is measured with heat wire anemometry. Measurement of the pressure yields the pressure drop in the model and this serves as criterion for the water level drop. Flow velocity is also determined by a laser Doppler measuring method. The results are used in computer models. The use of this model technique is demonstrated on a hydraulic engineering problem of the Oder River near Reitwein.
Schlagwörter Laserdoppleranemometrie (LDA)
Fließgeschwindigkeit
Wirbel
Druckmessung
Buhnenfeld
Buhne
HDA
Hitzdraht-Anemometrie
Parallelwerk
Sohlstromlinien
Messportal
Erosionsverfahren
Laserscanbefliegung
Odermodell
Luftströmung
aerodynamisches Modell
Wasserbau
hydraulic engineering
aeodynamical model
air current
Oder model
laserscan flight
erosion method
measuring portal
bottom streamlines
training wall
hot wire anemometry
HWA
groyne
groyne field
pressure measurement
vortices
flow velocity
laser Doppler anemometry
LDA

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