Predicting Atmospheric Icing and its Impact on Overhead Contact Wires
(2026) MVKM01 20261Department of Energy Sciences
- Abstract
- Ice accretion on overhead contact lines poses a significant challenge in the dimensioning of the railway system. The accreted ice will impose an additional vertical load from its self-weight and affect the wind loads by changing the wires cross-sectional area and shape. The current dimensioning methods, used by Trafikverket, often rely on simplified approximations and constant values when calculating the effects of wind and ice loads.
While the approach has not led to any known issues, more accurate calculations are desired to not needlessly overdimension the system.
This thesis aims to, with the use of Computational Fluid Dynamics (CFD), evaluate
the current way of calculating ice and wind loads. This is done by simulating in-cloud... (More) - Ice accretion on overhead contact lines poses a significant challenge in the dimensioning of the railway system. The accreted ice will impose an additional vertical load from its self-weight and affect the wind loads by changing the wires cross-sectional area and shape. The current dimensioning methods, used by Trafikverket, often rely on simplified approximations and constant values when calculating the effects of wind and ice loads.
While the approach has not led to any known issues, more accurate calculations are desired to not needlessly overdimension the system.
This thesis aims to, with the use of Computational Fluid Dynamics (CFD), evaluate
the current way of calculating ice and wind loads. This is done by simulating in-cloud icing, more specifically rime ice, in the software ANSYS FENSAP-ICE followed by flow simulations in ANSYS FLUENT for the drag coefficients.
A parametric study during the ice accretion simulations showed how different meteorological parameters will have a slight effect on the final ice shape. Thereafter the fluid simulations in FLUENT were conducted using both Unsteady Reynolds-Averaged Navier-Stokes (URANS) and Large Eddy Simulation (LES) to determine the drag coefficients for both non-iced and iced contact wires. The results were validated against experimental wind tunnel testing.
The results showed how the drag coefficients of the iced contact wires have a dependency on the meteorological parameters under which the ice was accreted. Additionally the flow simulations showed how the current assumptions, for both the clean and iced contact wire, may underestimate wind loads due to an underestimation of the drag coefficient. Furthurmore, the fluid simulations showed a strong dependency of the simulation setup, especially with regards to the chosen turbulence model, where LES provided substantially better force predictions.
From the gathered ice geometries and drag coefficients, as well as empirical formulas and correlations, a dynamic ice accretion model is presented. While the model contains rough approximations for geometric shapes and meteorological conditions, it demonstrates the benefit of using a dynamic model, as opposed to the today’s static assumptions, during dimensioning of the overhead contact line system. (Less) - Popular Abstract
- How can we predict icing and loads on contact wires?
Icing on contact wires can cause major disturbance to railway operations. The
ability to predict ice and wind loads can both make operation more reliable
and less costly. This paper investigates how computer simulations can be of
aid to determine the combined ice and wind loads.
Transport by railway has been of key importance for societal development since its introduction in the early 19th century. Since the start of railway electrification in the later half of the 19th century, leading up to modern times it has also proven to be an energy efficient and generally non-polluting mode of passenger and freight traffic.
In countries with colder climates the overhead contact... (More) - How can we predict icing and loads on contact wires?
Icing on contact wires can cause major disturbance to railway operations. The
ability to predict ice and wind loads can both make operation more reliable
and less costly. This paper investigates how computer simulations can be of
aid to determine the combined ice and wind loads.
Transport by railway has been of key importance for societal development since its introduction in the early 19th century. Since the start of railway electrification in the later half of the 19th century, leading up to modern times it has also proven to be an energy efficient and generally non-polluting mode of passenger and freight traffic.
In countries with colder climates the overhead contact lines, that are supposed to transfer power to the running trains, are subjected to ice accretion. With ice on the wires, additional forces from both the ice’s own weight and increased wind loads has to be taken into consideration when the system is dimensioned to ensure safe operation.
Currently there exists a limited amount of research and models of how to predict ice growth as well as the underlying parameters. The study therefore aims, with the help of computer simulations, to construct an icing model capable of being refined in the future when better estimations of certain variables exists.
With the use of computational fluid dynamics (CFD), ice is simulated on contact wires followed by a wind load study. The results in the paper are also validated with data from wind tunnel experiments, that was carried out in the scope of the project.
The paper shows that ice and wind loads resulting from the accreted ice under user defined meteorological conditions can be simulated, and yields results comparable to modern standards. This model would, if refined, make it possible to determine region specific thresholds for dimensioning. Alternatively it could be used with weather forecasts to determine ice levels on wires in real time.
An implementation of the presented model could be used to monitor ice loads along the railway system, or other similar structures like power cables. This would enable the owners of the infrastructure to effectively allocate resources and prohibit ice formations, alternatively repair eventual breakages in a time efficient manner. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/student-papers/record/9236667
- author
- Ferngren, Linus LU and Flygare, Axel LU
- supervisor
- organization
- course
- MVKM01 20261
- year
- 2026
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Atmospheric icing, Computational Fluid Dynamics, CFD, Rime ice, Ice accretion, Contact wire, Overhead contact line, Wind tunnel, Aerodynamic load
- report number
- ISRN: LUTMDN/TMHP-26/5676-SE
- ISSN
- 0282-1990
- language
- English
- id
- 9236667
- date added to LUP
- 2026-06-17 14:50:28
- date last changed
- 2026-06-17 14:50:28
@misc{9236667,
abstract = {{Ice accretion on overhead contact lines poses a significant challenge in the dimensioning of the railway system. The accreted ice will impose an additional vertical load from its self-weight and affect the wind loads by changing the wires cross-sectional area and shape. The current dimensioning methods, used by Trafikverket, often rely on simplified approximations and constant values when calculating the effects of wind and ice loads.
While the approach has not led to any known issues, more accurate calculations are desired to not needlessly overdimension the system.
This thesis aims to, with the use of Computational Fluid Dynamics (CFD), evaluate
the current way of calculating ice and wind loads. This is done by simulating in-cloud icing, more specifically rime ice, in the software ANSYS FENSAP-ICE followed by flow simulations in ANSYS FLUENT for the drag coefficients.
A parametric study during the ice accretion simulations showed how different meteorological parameters will have a slight effect on the final ice shape. Thereafter the fluid simulations in FLUENT were conducted using both Unsteady Reynolds-Averaged Navier-Stokes (URANS) and Large Eddy Simulation (LES) to determine the drag coefficients for both non-iced and iced contact wires. The results were validated against experimental wind tunnel testing.
The results showed how the drag coefficients of the iced contact wires have a dependency on the meteorological parameters under which the ice was accreted. Additionally the flow simulations showed how the current assumptions, for both the clean and iced contact wire, may underestimate wind loads due to an underestimation of the drag coefficient. Furthurmore, the fluid simulations showed a strong dependency of the simulation setup, especially with regards to the chosen turbulence model, where LES provided substantially better force predictions.
From the gathered ice geometries and drag coefficients, as well as empirical formulas and correlations, a dynamic ice accretion model is presented. While the model contains rough approximations for geometric shapes and meteorological conditions, it demonstrates the benefit of using a dynamic model, as opposed to the today’s static assumptions, during dimensioning of the overhead contact line system.}},
author = {{Ferngren, Linus and Flygare, Axel}},
issn = {{0282-1990}},
language = {{eng}},
note = {{Student Paper}},
title = {{Predicting Atmospheric Icing and its Impact on Overhead Contact Wires}},
year = {{2026}},
}