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Civil-Comp Proceedings
ISSN 1759-3433
CCP: 110
PROCEEDINGS OF THE THIRD INTERNATIONAL CONFERENCE ON RAILWAY TECHNOLOGY: RESEARCH, DEVELOPMENT AND MAINTENANCE
Edited by: J. Pombo
Paper 50

Representing Large Boundary Layers in Slipstream Moving Model Tests

M. Sima1, A. Tietze2, B. Schulz2 and K. Ehrenfried3

1Centre of Competence Aero- and Thermodynamics,Bombardier Transportation, Sweden
2Centre of Competence Aero- and Thermodynamics, Bombardier Transportation, Germany
3German Aerospace Centre, Göttingen, Germany

Full Bibliographic Reference for this paper
M. Sima, A. Tietze, B. Schulz, K. Ehrenfried, "Representing Large Boundary Layers in Slipstream Moving Model Tests", in J. Pombo, (Editor), "Proceedings of the Third International Conference on Railway Technology: Research, Development and Maintenance", Civil-Comp Press, Stirlingshire, UK, Paper 50, 2016. doi:10.4203/ccp.110.50
Keywords: train, slipstream, moving model, measurements, roughness elements, boundary layer generation, interoperability.

Summary
The induced slipstream of a passing modern passenger train reaches its peak velocities in the wake, the magnitude of which is limited by authorisation requirements. The induced velocity is influenced by the boundary layer reaching the train rear, requiring longer trains to be studied, while the suitable predictive method of moving model tests have limitations on the possible model length. This paper presents a first attempt to generate varying boundary layers with a limited model length in moving model tests of slipstream airflows, to be able to represent longer train lengths than possible with the model facility. Comparisons are made to full scale data of loco-hauled DoSto cars with rear driving trailer over two platform heights at different train speeds, and at trackside. With roughness elements on a fore-body the boundary layer size can be varied significantly. Having roughness improves the prediction over the platform configurations. Some questions remain about the trackside measurements where there is a larger discrepancy, including what influence the representation of the ground has, which is different than in the full scale tests.

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