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Investigating side-wind stability of high speed trains using high resolution large eddy simulations and hybrid models

Investigating side-wind stability of high speed trains using high resolution large eddy simulations and hybrid models
Investigating side-wind stability of high speed trains using high resolution large eddy simulations and hybrid models
Crosswind flow over high speed trains can pose serious safety concerns for rail transport. Methodologies for evaluating the aerodynamic forces exerted on the train include full-scale measurements, physical modeling using wind-tunnel experiments and numerical modeling using computational fluid mechanics (CFD). Although CFD presents the most cost-effective approach, it faces severe uncertainties in the predicted forces, most of which are related to the turbulence modeling technique employed. In here we investigate the influence of various turbulence modeling approaches on crosswind flow simulations and calculated force coefficients. In particular, we perform URANS, LES and DDES simulations utilizing the DLR Next Generation Train 2 model geometry. Particular emphasis is laid on simulating a wind angle of 30! and Reynolds number of 225,000 for which validation data is provided by wind tunnel measurements. We confirm that a major vortex system on the leeward side of the train develops, which mainly drives the overturning force and moment of the train. The lift force is determined mainly by the underbody flow, which is characterized by unsteady vortex shedding. Due to its dual ability to properly model the roof boundary layer on the one hand and to resolve small-scale turbulent eddies in the underfloor region on the other, the DDES approach is found to give the most accurate force predictions. LES overpredicts the overturning force and moment, while URANS overpredicts the lift force.
223-241
Springer
Fragner, Moritz M.
60b4ceec-abe8-49b3-933b-eefd2ad1ab84
Deiterding, Ralf
ce02244b-6651-47e3-8325-2c0a0c9c6314
Diez, P.
Neittaanmäki, P.
Periaux, J.
Tuovinen, T.
Bräysy, O.
Fragner, Moritz M.
60b4ceec-abe8-49b3-933b-eefd2ad1ab84
Deiterding, Ralf
ce02244b-6651-47e3-8325-2c0a0c9c6314
Diez, P.
Neittaanmäki, P.
Periaux, J.
Tuovinen, T.
Bräysy, O.

Fragner, Moritz M. and Deiterding, Ralf (2018) Investigating side-wind stability of high speed trains using high resolution large eddy simulations and hybrid models. In, Diez, P., Neittaanmäki, P., Periaux, J., Tuovinen, T. and Bräysy, O. (eds.) Computation Methods & Models for Transport. ECCOMAS 2015. (Computational Methods in Applied Sciences, 45) Cham. Springer, pp. 223-241. (doi:10.1007/978-3-319-54490-8_14).

Record type: Book Section

Abstract

Crosswind flow over high speed trains can pose serious safety concerns for rail transport. Methodologies for evaluating the aerodynamic forces exerted on the train include full-scale measurements, physical modeling using wind-tunnel experiments and numerical modeling using computational fluid mechanics (CFD). Although CFD presents the most cost-effective approach, it faces severe uncertainties in the predicted forces, most of which are related to the turbulence modeling technique employed. In here we investigate the influence of various turbulence modeling approaches on crosswind flow simulations and calculated force coefficients. In particular, we perform URANS, LES and DDES simulations utilizing the DLR Next Generation Train 2 model geometry. Particular emphasis is laid on simulating a wind angle of 30! and Reynolds number of 225,000 for which validation data is provided by wind tunnel measurements. We confirm that a major vortex system on the leeward side of the train develops, which mainly drives the overturning force and moment of the train. The lift force is determined mainly by the underbody flow, which is characterized by unsteady vortex shedding. Due to its dual ability to properly model the roof boundary layer on the one hand and to resolve small-scale turbulent eddies in the underfloor region on the other, the DDES approach is found to give the most accurate force predictions. LES overpredicts the overturning force and moment, while URANS overpredicts the lift force.

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Accepted/In Press date: 1 November 2016
e-pub ahead of print date: 30 June 2017
Published date: 1 May 2018
Organisations: Aerodynamics & Flight Mechanics Group

Identifiers

Local EPrints ID: 404191
URI: http://eprints.soton.ac.uk/id/eprint/404191
PURE UUID: c38e2e48-ac0a-4743-b640-c409c4dccb49
ORCID for Ralf Deiterding: ORCID iD orcid.org/0000-0003-4776-8183

Catalogue record

Date deposited: 03 Jan 2017 14:45
Last modified: 26 Nov 2021 03:04

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Contributors

Author: Moritz M. Fragner
Author: Ralf Deiterding ORCID iD
Editor: P. Diez
Editor: P. Neittaanmäki
Editor: J. Periaux
Editor: T. Tuovinen
Editor: O. Bräysy

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