Institut für Hydromechanik
Facing Global Warming: Making Cities more Livable

Laboratory studies of nightly cold air drainage into the German city of Mannheim were performed. The incentive was to mitigate the urban heat island (UHI) effect which impacts dweller’s health and impairs sleep quality in hot summer nights. Colder air from the rural surroundings can cool down city air temperature and contribute to improved living and health conditions.

The movie shows the flow of simulated cold air as it was studied at scaled models for the present and the projected future state tailored to the improved intrusion of cold air flow into the city center. In subsequent film clips cold air flows in the present and future state are compared for various subareas and filmed from different perspectives.

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IfH Forschung im Fernsehen

Der TV-Beitrag, gedreht vom Bayrischen Rundfunk für die Wissenschaftssendungen „Gut zu Wissen“ (BR) und  „Xenius“ (Arte), beschäftigt sich mit Alleenbäumen und Heckenreihen in städtischen Straßenschluchten. Es werden deren Einflüsse auf die natürliche Ventilation erläutert und die damit verbundenen Auswirkungen auf die Vermischung und den Abtransport von im Straßenraum freigesetzten Verkehrsemissionen betrachtet.

Während Alleenbaumreihen zu einem Anstieg von verkehrsbedingten Schadstoffkonzentrationen führen, weil sie die natürliche Ventilation einschränken, wirken sich Heckenreihe positiv auf die Luftqualität im Straßenraum aus.

Weitere Informationen und Daten zu dem Forschungsprojekt sind hier zu finden:

EUROMECH Colloquium

- Postponed due to Covid19 Emergency -
"Granular Patterns in Oscillatory Flows" from Sept 07 - 10, 2021 in Genoa, Italy


The physics underlying the transport of particles and the particle collective attitude to originate geometrical patterns in oscillatory flows is the main scope of the colloquium. Contributions concerning turbulence and particle dynamics are favoured. Nonetheless, geomorphological, chemical and biological aspects strictly related to the mechanics of particulate oscillatory flows are considered of great relevance for the colloquium. Indeed, the multidisciplinarity of the contributions is believed fundamental for a successful colloquium. The colloquium can be attended by participation only.

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More information
MOAT project successful in large-scale Gauss call

The MOAT project ("micro-organisms and turbulence") has just been awarded a massive amount of computational resources at the Stuttgart super-computing center HLRS through the highly-competitive selection process coordinated by the Gauss Center for Supercomputing (GCS).
The simulations will consider the fate of bacteria in turbulent open channel flow over a realistic sediment bed, including a faithful representation of the dynamics of suspended particles and of additional scalar fields.
A link to the result of the 20th GCS call for large-scale projects can be found here. 
More information on the science behind the MOAT project can be found here.

Direct Numerical Simulation of the Formation of Subaqueous Sediment Patterns: Evolution Beyond the Initial Formation

This project has investigated the problem of sediment transport and subaqueous pattern formation by means of high-fidelity direct numerical simulations which resolve all the relevant scales of the flow and the sediment bed. In order to realistically capture the phenomenon, sufficiently large computational domains with up to several billion grid nodes are adopted, while the sediment bed is represented by up to a million mobile spherical particles. The study provides a unique set of spatially and temporally resolved information on the flow field and the motion of individual particles which make up the sediment bed, providing novel insight into the different mechanisms involved in the processes of sediment pattern formation.

Direct Numerical Simulation of Fully-Rough Open-Channel Flow Over Spherical Roughness Elements

Open channel flow can be considered as a convenient "laboratory" for investigating the physics of the flow in rivers. One open questions in this field is related to the influence of a rough boundary (i.e. the sediment bed) upon the hydraulic properties, which to date is still unsatisfactorily modelled by common engineering-type formulae. The present project aims to provide the basis for enhanced models by generating high-fidelity data of shallow flow over a bed roughened with spherical elements in the fully rough regime. In particular, the influence of the roughness Reynolds number and of the spatial roughness arrangement upon the turbulent channel flow structure is being studied.