Meeting on "Multiphase Flows - Advances and Future Directions", Oct. 28-30, 2021

The meeting - organized by the Complex Systems and Dynamics group from the IIT Madras - was held in recognition of the accomplishments of S. "Bala" Balachandar and in celebration of his 60th birthday. 
The focus was to learn and understand the world of multiphase flow dynamics through research seminars by experts in the field. Check out the talk given by Markus Uhlmann on YouTube:  "Investigating turbulent particulate flows with the aid of invariant solutions".


More information on the entire conference
Two Postdoctoral Positions (2-years) in an interdisciplinary project

We are looking for 2 postdoctoral researchers in Ice Multiplication – Solving the longest standing puzzle in cloud physics to work for 2 years across scales and with different experimental and computational methods.
he work plan for the two positions will be defined in a dialogue between the postdoctoral researchers and the PIs. Both positions are available from 1st February 2022 or as soon as possible thereafter. For details, please refer to our job openings site.
Review of applications for the positions will start on December 15, 2021, and will continue until the positions are filled.

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colloquiumgauss centre
HLRS 'Golden Spike Award' for Markus Scherer, MSc.

Every year the steering committee of HLRS chooses three particularly excellent projects to honor them with a special trophy: The HLRS Golden Spike Award. We are proud that Markus Scherer is among the winners 2021!

Markus received the Golden Spike Award for his project RIDGEWAV ("Secondary flow and longitudinal sediment patterns in turbulent channel flow over a bed of mobile particles in domains of small to intermediate size").

Decision criteria for the award include:

1. Scientific relevance (top in their research field)

2. Imperative of high-performance computing for their research

3. Optimal usage of HPC equipment in terms of optimization, parallelization, and overall performance

4. Presentation format of the results at the Results and Review Workshop.


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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.


Watch the Movie
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.


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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.