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1

Streamlined topographical features in and around the Gulf of Riga as evidence of Late Weichselian glacial dynamics

Tsyrulnikov A., Tuuling I., Hang T.

Geological Quarterly

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2008

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Vol. 52, No 1

81-81

EN

Based on various cartographic sources, a digital terrain model and acoustic profiling data, linear relief features of glacial origin have been distin guished and analysed in the Gulf of Riga and adjacent mainland areas in order to reconstruct the dynamics and pathways of former ice streams. North-east–south-west oriented features in the till topography prevail in the central part of the gulf and along the southern coast of the island of Saaremaa, which corroborate the previously known south/south-east di rection of the main Riga ice stream. North-east to south-west directed features dominate in the Pärnu Bay and around the Irbe Strait. Similar deviations from the Riga ice stream are most likely due to ice divide zones, namely the Sakala Upland in Southern Estonia and Kurzeme in north western Latvia, which locally changed the course of the main ice flow. The influence of the Kurzeme ice divide is traceable at the bottom of the gulf up to the southern coast of Saaremaa. There is no evidence of an ice-marginal zone cross ing the central part of the Gulf of Riga as was supposed earlier. The Pandivere-Neva and Palivere ice-marginal zones, which merge on the Sorve Peninsula, probably continue offshore into the Irbe Strait. As the age of the glacier relieffeatures is poorly contained, the chronologi reconstruction of the ice dynamics is tentative.

2

Simulation of the shorelines of glacial Lake Peipsi in Eastern Estonia during the Late Weichselian

Rosentau A., Hang T., Miidel A.

Geological Quarterly

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2004

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Vol. 48, No 4

299--307

EN

Digital reconstruction of the evolution of glacial Lake Peipsi, Eastern Estonia, was based on a geographic information system (GIS) method that removed isostatically deformed palaeowater planes fromthe current digital terrain model. A reconstruction of the proglacial water levels was performed with respect to geomorphological correlation of river terraces, raised shorelines and eroded surfaces of various aqueoglacial landforms. The configuration of shorelines, main outlets and water depths of glacial Lake Peipsi, corresponding to the Otepää, Piirissaar, Kaiu and Pandivere–Neva stades during the deglaciation of the Lake Peipsi depression, was simulated. The two approaches used, reflecting the geomorphological correlation of Raukas and Rähni (1969) and Hang (2001), are discussed.

3

Calculation of the influence of propeller operation on the hydrodynamic characteristics of the rudder

Hang T.

Polish Maritime Research

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2001

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Vol. 8, nr 2

3-9

EN

The paper presents a lifting surface method for calculation of the hydrodynamic characteristics of the rudder in the propeller slipstream. Flow velocity induced by the propeller in given points on the rudder is calculated. Pressure distribution, lift and drag of the rudder is computed with taking into account propeller interaction. The calculation results show good consistence with experimental data.