{ "types" : { "Bookmark" : { "pluralLabel" : "Bookmarks" }, "Publication" : { "pluralLabel" : "Publications" }, "GoldStandardPublication" : { "pluralLabel" : "GoldStandardPublications" }, "GoldStandardBookmark" : { "pluralLabel" : "GoldStandardBookmarks" }, "Tag" : { "pluralLabel" : "Tags" }, "User" : { "pluralLabel" : "Users" }, "Group" : { "pluralLabel" : "Groups" }, "Sphere" : { "pluralLabel" : "Spheres" } }, "properties" : { "count" : { "valueType" : "number" }, "date" : { "valueType" : "date" }, "changeDate" : { "valueType" : "date" }, "url" : { "valueType" : "url" }, "id" : { "valueType" : "url" }, "tags" : { "valueType" : "item" }, "user" : { "valueType" : "item" } }, "items" : [ { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/23e33e6e002f2afa931f4a9e41ae15770/andreasruopp", "tags" : [ "CFD","OpenFOAM","benchmark","computer","myown","performance" ], "intraHash" : "3e33e6e002f2afa931f4a9e41ae15770", "interHash" : "f9244d0718087a8a04b5a1e3bb234e39", "label" : "Performance Comparison of CFD Microbenchmarks on Diverse HPC Architectures", "user" : "andreasruopp", "description" : "", "date" : "2024-07-19 12:28:17", "changeDate" : "2024-07-19 12:28:17", "count" : 1, "pub-type": "article", "journal": "Computers", "year": "2024", "url": "https://www.mdpi.com/2073-431X/13/5/115", "author": [ "Flavio C. C. Galeazzo","Marta Garcia-Gasulla","Elisabetta Boella","Josep Pocurull","Sergey Lesnik","Henrik Rusche","Simone Bnà","Matteo Cerminara","Federico Brogi","Filippo Marchetti","Daniele Gregori","R. Gregor Weiß","Andreas Ruopp" ], "authors": [ {"first" : "Flavio C. C.", "last" : "Galeazzo"}, {"first" : "Marta", "last" : "Garcia-Gasulla"}, {"first" : "Elisabetta", "last" : "Boella"}, {"first" : "Josep", "last" : "Pocurull"}, {"first" : "Sergey", "last" : "Lesnik"}, {"first" : "Henrik", "last" : "Rusche"}, {"first" : "Simone", "last" : "Bnà"}, {"first" : "Matteo", "last" : "Cerminara"}, {"first" : "Federico", "last" : "Brogi"}, {"first" : "Filippo", "last" : "Marchetti"}, {"first" : "Daniele", "last" : "Gregori"}, {"first" : "R. Gregor", "last" : "Weiß"}, {"first" : "Andreas", "last" : "Ruopp"} ], "volume": "13","number": "5","abstract": "OpenFOAM is a CFD software widely used in both industry and academia. The exaFOAM project aims at enhancing the HPC scalability of OpenFOAM, while identifying its current bottlenecks and proposing ways to overcome them. For the assessment of the software components and the code profiling during the code development, lightweight but significant benchmarks should be used. The answer was to develop microbenchmarks, with a small memory footprint and short runtime. The name microbenchmark does not mean that they have been prepared to be the smallest possible test cases, as they have been developed to fit in a compute node, which usually has dozens of compute cores. The microbenchmarks cover a broad band of applications: incompressible and compressible flow, combustion, viscoelastic flow and adjoint optimization. All benchmarks are part of the OpenFOAM HPC Technical Committee repository and are fully accessible. The performance using HPC systems with Intel and AMD processors (x86\\_64 architecture) and Arm processors (aarch64 architecture) have been benchmarked. For the workloads in this study, the mean performance with the AMD CPU is 62\\% higher than with Arm and 42\\% higher than with Intel. The AMD processor seems particularly suited resulting in an overall shorter time-to-solution.", "issn" : "2073-431X", "article-number" : "115", "doi" : "10.3390/computers13050115", "bibtexKey": "computers13050115" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/25c85a2c5a90952c373b9a9a4a95fef77/andreasruopp", "tags" : [ "CFD","Hemodynamics","MRI","OpenFOAM","Optimisation","myown" ], "intraHash" : "5c85a2c5a90952c373b9a9a4a95fef77", "interHash" : "554fd40aeed0597a3a3493e5b3295be6", "label" : "MRI-Based Computational Hemodynamics in Patients", "user" : "andreasruopp", "description" : "", "date" : "2023-05-03 10:18:16", "changeDate" : "2023-05-03 10:18:16", "count" : 2, "pub-type": "inproceedings", "booktitle": "Sustained Simulation Performance 2017","publisher":"Springer International Publishing","address":"Cham", "year": "2017", "url": "", "author": [ "Andreas Ruopp","Ralf Schneider" ], "authors": [ {"first" : "Andreas", "last" : "Ruopp"}, {"first" : "Ralf", "last" : "Schneider"} ], "editor": [ "Michael M. Resch","Wolfgang Bez","Erich Focht","Michael Gienger","Hiroaki Kobayashi" ], "editors": [ {"first" : "Michael M.", "last" : "Resch"}, {"first" : "Wolfgang", "last" : "Bez"}, {"first" : "Erich", "last" : "Focht"}, {"first" : "Michael", "last" : "Gienger"}, {"first" : "Hiroaki", "last" : "Kobayashi"} ], "pages": "165--178","abstract": "The target of this research was to develop a simulation process chain for the analysis of arterial hemodynamics in patients with automatic calibration of all boundary conditions for the physiological correct treatment of flow rates in transient blood flows with multiple bifurcations. The developed methodology uses stationary simulations at peak systolic acceleration and minimizes the error of target and simulated outflow conditions by means of a parallel genetic optimization approach. The target inflow and outflow conditions at peak systole are extracted from 4D phase contrast magnetic resonance imaging (4D PC-MRI). The flow resistance of the arterial system lying downstream of the simulation domain's outlets is modelled via porous media with velocity dependent loss coefficients. In the analysis of the subsequent transient simulations, it will be shown that the proposed calibration method shows to work suitable for three different types of patients including one healthy patient, a patient suffering from an aneurysm as well as one with a coarctation. Additionally the local effects of mapping the measured transient 4D PC-MRI data onto the aortic valve inlet in comparison to the usage of block inlet profiles will be shown.", "isbn" : "978-3-319-66896-3", "bibtexKey": "10.1007/978-3-319-66896-3_11" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/206320a1de56967ea5839cd30644e1bb3/andreasruopp", "tags" : [ "AirPollution","CFD","CoupledSimulation","UrbanScale" ], "intraHash" : "06320a1de56967ea5839cd30644e1bb3", "interHash" : "1d16326b62ec0600c0a2f4d2457d1ae6", "label" : "Multi-scale Modelling of Urban Air Pollution with Coupled Weather Forecast and Traffic Simulation on HPC Architecture", "user" : "andreasruopp", "description" : "", "date" : "2023-05-03 09:48:23", "changeDate" : "2023-05-03 09:48:23", "count" : 1, "pub-type": "inproceedings", "booktitle": "The International Conference on High Performance Computing in Asia-Pacific Region Companion","series": "HPC Asia 2021","publisher":"Association for Computing Machinery","address":"New York, NY, USA", "year": "2021", "url": "https://doi.org/10.1145/3440722.3440917", "author": [ "Laszlo Kornyei","Zoltan Horvath","Andreas Ruopp","Akos Kovacs","Bence Liszkai" ], "authors": [ {"first" : "Laszlo", "last" : "Kornyei"}, {"first" : "Zoltan", "last" : "Horvath"}, {"first" : "Andreas", "last" : "Ruopp"}, {"first" : "Akos", "last" : "Kovacs"}, {"first" : "Bence", "last" : "Liszkai"} ], "pages": "9\u201310","abstract": "Urban air pollution is one of the global challenges to which over 3 million deaths are attributable yearly. Traffic is emitting over 40% of several contaminants, like NO2 [10]. The directive 2008/50/EC of the European Commission prescribes the assessment air quality by accumulating exceedance of contamination concentration limits over a one-year period using measurement stations, which may be supplemented by modeling techniques to provide adequate information on spatial distribution. Computational models do predict that small scale spatial fluctuation is expected on the street level: local air flow phenomena can cluster up pollutants or carry them away far from the location of emission [2]. The spread of the SARS-CoV-2 virus also interacts with urban air quality. Regions in lock down have highly reduced air pollution strain due to the drop of traffic [4]. Also, correlation between the fatality rate of a previous respiratory disease, SARS 2002, and Air Pollution Index suggests that bad air quality may double fatality rate [6]. At street level pollution dispersion highly depends on the daily weather, a one-year simulation low time scale model is needed. Additionally, to resolve street-level phenomena a cell size of 1 to 4 meters are utilized in these regions that requires CFD methods to use a simulation domain of 1 to 100 million cells. Memory and computational requirements for these tasks are enormous, so HPC architecture is needed to have reasonable results within a manageable time frame. To tackle this challenge, the Urban Air Pollution (UAP) workflow is developed as a pilot of the HiDALGO project [7], which is funded by the H2020 framework of the European Union. The pilot is designed in a modular way with the mindset to be developed into a digital twin model later. Its standardized interfaces enable multiple software to be used in a specific module. At its core, a traffic simulation implemented in SUMO is coupled with a CFD simulation. Currently OpenFOAM (v1906, v1912 and v2006) and Ansys Fluent (v19.2) are supported. This presentation focuses on the OpenFOAM implementation, as it proved more feasible and scalable on most HPC architectures. The incompressible unsteady Reynolds-averaged Navier\u2013 Stokes equations are solved with the PIMPLE method, Courant-number based adaptive time stepping and transient atmospheric boundary conditions. The single component NOx-type pollution is calculated independently as a scalar with transport equations along the flow field. Pollution emission is treated as a per cell volumetric source that changes in time. The initial condition is obtained from a steady state solution at the initial time with the SIMPLE method, using the identical, but stationary boundary conditions and source fields. Custom modules are developed for proper boundary condition and source term handling. The UAP workflow supports automatic 3D air flow geometry and traffic network generation from OpenStreetMap data. Ground and building information are used for geometry, road network for traffic, and further assets for visualization. The CFD 3D mesh generation is done by either an in-house octree-mesh generator, or the snappyHexMesh utility from OpenFOAM. Meteorological data for boundary conditions are acquired from ECMWF using the Polytope REST API [5] automatically for the user specified day and location. The values at the closes grid point is selected, transformed into the Euclidean coordinate system, and converted OpenFOAM readable file format. A custom OpenFOAM module ensures the proper handling of the altitude and time dependent boundary field. Background air quality data is acquired from the Copernicus AMS [3]. Results are validated against a local air quality sensor network which is under expansion for more accuracy. Traffic simulation or data can be obtained from external sources. For the pilot, a traffic sensor network of camera and loop detectors are installed in the Hungarian city of Győr. Sensory data is transmitted real time and is to be coupled into the simulation directly. Random traffic generation is also supported. Emission is computed by an in-house tool from traffic simulation results in SUMO data file format by applying the Copert model, interpolated to the CFD mesh and stored to an OpenFOAM readable file format. A custom OpenFOAM module is responsible for the timely read of this source term data and the proper adjustments on the equations. Calculation of the wind flow and the pollution dispersion is the most computationally heavy part of the workflow, as input file generation and traffic simulation top at 60 and 20 minutes on one node, respectively, for one day, in comparison to the minimum 2 hours for the smallest cell count CFD model. For benchmarking purposes, only the runtime of a small portion (15-60 minutes) of the scalable part of the OpenFOAM simulation is measured for the transient and 600 iterations for the steady state simulation. Primary benchmarks are issued on the local cluster PLEXI (18 node 2x6 core Intel X5650, 48GB RAM, 40Gb InfiniBand) with additional investigations on EAGLE (PSNC, Poznan, 1119 node 2x14 core Intel E5-2697v3, 64GB RAM, 56Gb InfiniBand) and the HAWK Test System (HLRS, Stuttgart, 5632 node 2x128 core AMD EPYC 7742, 256GB RAM, 200 Gb InfiniBand HDR200). Tuning OpenFOAM settings with optimized IO, multilevel decomposition and cell index renumbering improved speedup on PLEXI from 18 to 102 for the 1M cell count and from 49 to 77 on the 9M cell count model at 216 cores. On the HAWK Test System, speedups top at 133 for 1M and 401 for 9M cells, both at 2048 cores. On EAGLE, the 1M cell count model tops speedup at 104 at 448 cores. Saturating effect at one node core count suggests memory bandwidth limited calculations. Full day simulation runs were also done for areas within 5 cities (Győr, Madrid, Stuttgart, Herrenberg and Graz) with random traffic and different mesh sizes of ca. 0.8M and ca. 3M cells. The runtime of the full CFD module on PLEXI at 48 cores in 2.7 and 20 hours on average for the smaller and larger cell count, respectively. This puts the one-year simulation within reach for coarse meshes on PLEXI and finer meshes on the more powerful HPC architectures. Due to a high core count to memory channel ratio for AMD processors, poor single node parallel efficiency is expected on memory bandwidth limited applications, which supports our present findings, and are comparable with speedup results of other CFD software on the same hardware [9]. Node based speedup of certain OpenFOAM simulations, however, may show superlinear behavior [1]. In conclusion, the UAP workflow and the OpenFOAM implementation of the CFD module are on good track for reaching the goal of simulating one year within a manageable time frame. The few hours long simulation time for one day\u2019s pollution also makes the current version feasible for forecasting. Future work includes using proper orthogonal decomposition, POD[8], which is a model order reduction method for eventually improving calculation time drastically while sacrificing limited accuracy. We also plan testing and benchmarking GPGPU based solvers, implementing reaction for pollutants and extend validation using new air quality measuring stations.", "isbn" : "9781450383035", "location" : "Virtual Event, Republic of Korea", "doi" : "10.1145/3440722.3440917", "bibtexKey": "Kornyei2021" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/24e65532c85404ad17b817ec91c9703c5/andreasbaumann", "tags" : [ "cfd","myown","sld","sph" ], "intraHash" : "4e65532c85404ad17b817ec91c9703c5", "interHash" : "630ba3441a51d24560fb9d43e51b4ae7", "label" : "Geometry modifications of single-lip drills to improve cutting fluid flow", "user" : "andreasbaumann", "description" : "", "date" : "2022-06-01 13:58:24", "changeDate" : "2022-06-22 06:27:03", "count" : 2, "pub-type": "article", "journal": "The International Journal of Advanced Manufacturing Technology", "year": "2022", "url": "https://doi.org/10.1007/s00170-022-09400-z", "author": [ "Andreas Baumann","Ekrem Oezkaya","Dirk Biermann","Peter Eberhard" ], "authors": [ {"first" : "Andreas", "last" : "Baumann"}, {"first" : "Ekrem", "last" : "Oezkaya"}, {"first" : "Dirk", "last" : "Biermann"}, {"first" : "Peter", "last" : "Eberhard"} ], "volume": "121","number": "3","pages": "1689\u20131695","abstract": "For single-lip drills with small diameters, the cutting fluid is supplied through a kidney-shaped cooling channel inside the tool. In addition to reducing friction, the cutting fluid is also important for the dissipation of heat at the cutting edge and for the chip removal. However, in previous investigations of single-lip drills, it was observed that the fluid remains on the back side of the cutting edge, and accordingly, the cutting edge is insufficiently cooled. In this paper, a simulation-based investigation of an introduced additional drainage flute and flank surface modifications is carried out using smoothed particle hydrodynamics as well as computational fluid dynamics. It is determined that the additionally introduced drainages lead to a slightly changed flow situation, but a significant flow behind the cutting edge and into the drainage flute cannot be achieved due to reasons explained in this paper. Accordingly, not even a much larger drainage flute with unwanted side-effect of a decrease tool strength is able to archive a significant improvement of the flow around the cutting edge. Therefore, major changes to the cooling channel, like the use of two separate channels, the modification of their positions, or modified flank surfaces, are necessary in order to achieve an improvement in lubrication of the cutting edge and heat dissipation.", "issn" : "1433-3015", "doi" : "10.1007/s00170-022-09400-z", "bibtexKey": "BaumannEtAl22" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2cda17119e56b6f9409da7bbd427db079/andreasbaumann", "tags" : [ "cfd","dem","myown","sld","sph" ], "intraHash" : "cda17119e56b6f9409da7bbd427db079", "interHash" : "546d46b1bcf027f9d42cad546fb07cd7", "label" : "Analysis of the cutting fluid behavior with a modified micro single-lip deep hole drilling tool", "user" : "andreasbaumann", "description" : "", "date" : "2022-05-01 12:08:54", "changeDate" : "2022-06-01 15:43:42", "count" : 1, "pub-type": "article", "journal": "CIRP Journal of Manufacturing Science and Technology","publisher":"Elsevier BV", "year": "2022", "url": "https://doi.org/10.1016%2Fj.cirpj.2022.04.003", "author": [ "Ekrem Oezkaya","Andreas Baumann","Peter Eberhard","Dirk Biermann" ], "authors": [ {"first" : "Ekrem", "last" : "Oezkaya"}, {"first" : "Andreas", "last" : "Baumann"}, {"first" : "Peter", "last" : "Eberhard"}, {"first" : "Dirk", "last" : "Biermann"} ], "volume": "38","pages": "93--104", "doi" : "10.1016/j.cirpj.2022.04.003", "bibtexKey": "Oezkaya_2022" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/239980fafb80e64ccfdceb78838cacf44/andreasbaumann", "tags" : [ "CFD","DEM","SLD","SPH","myown" ], "intraHash" : "39980fafb80e64ccfdceb78838cacf44", "interHash" : "55c4edef520940e0544cdaa01ea63701", "label" : "Cutting fluid behavior under consideration of chip formation during micro single-lip deep hole drilling of Inconel 718", "user" : "andreasbaumann", "description" : "", "date" : "2022-03-17 16:30:11", "changeDate" : "2022-04-12 13:23:17", "count" : 3, "pub-type": "article", "journal": "International Journal of Modelling and Simulation","publisher":"Taylor & Francis", "year": "2022", "url": "/brokenurl# https://doi.org/10.1080/02286203.2022.2042057 ", "author": [ "Ekrem Oezkaya","Andreas Baumann","Sebastian Michel","Dirk Schnabel","Peter Eberhard","Dirk Biermann" ], "authors": [ {"first" : "Ekrem", "last" : "Oezkaya"}, {"first" : "Andreas", "last" : "Baumann"}, {"first" : "Sebastian", "last" : "Michel"}, {"first" : "Dirk", "last" : "Schnabel"}, {"first" : "Peter", "last" : "Eberhard"}, {"first" : "Dirk", "last" : "Biermann"} ], "pages": "1-15","abstract": "ABSTRACTWhen micro-single-lip deep hole drilling the efficiency of the cutting fluid supply cannot be investigated experimentally due to the inaccessibility of the cutting zone. For this reason, this paper examines the cutting fluid behavior, taking into account the chip formation and the transient chip position, with the help of various combined simulation methods. Therefore, experimentally obtained chips are digitalized and converted into a Computer-Aided Design model for the following simulations. Furthermore, for a comparison of the simulations with the experiments, the velocity of the cutting fluid in the chip flute of the tool is measured by a similar Particle Image Velocimetry method. Then, a transient coupled particle simulation of Smoothed Particle Hydrodynamics and the Discrete Element Method is performed to obtain the transient chip positions along the chip flute under the influence of the cutting fluid. Based on these chip positions, a Computational Fluid Dynamics simulation follows to derive insights about the flow field and pressure field at certain points in time. This multi-physics simulation chain allows to deal with experimental results in a simulation context to gain further insights about the deep hole drilling process, which are experimentally inaccessible and allows further connections between experiment and simulation.", "eprint" : "https://doi.org/10.1080/02286203.2022.2042057", "doi" : "10.1080/02286203.2022.2042057", "bibtexKey": "doi:10.1080/02286203.2022.2042057" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/273aa5c254aa86fff5ebbc441b736e8a3/andreasbaumann", "tags" : [ "CFD","DEM","SPH","myown" ], "intraHash" : "73aa5c254aa86fff5ebbc441b736e8a3", "interHash" : "c1e079e7c3c447ed9255c49705d05fa7", "label" : "Cutting-fluid flow with chip evacuation during deep-hole drilling with twist drills", "user" : "andreasbaumann", "description" : "", "date" : "2022-03-17 16:22:22", "changeDate" : "2022-04-12 13:23:34", "count" : 2, "pub-type": "article", "journal": "European Journal of Mechanics - B/Fluids","publisher":"Elsevier BV", "year": "2021", "url": "https://doi.org/10.1016%2Fj.euromechflu.2021.07.003", "author": [ "Andreas Baumann","Ekrem Oezkaya","Dirk Schnabel","Dirk Biermann","Peter Eberhard" ], "authors": [ {"first" : "Andreas", "last" : "Baumann"}, {"first" : "Ekrem", "last" : "Oezkaya"}, {"first" : "Dirk", "last" : "Schnabel"}, {"first" : "Dirk", "last" : "Biermann"}, {"first" : "Peter", "last" : "Eberhard"} ], "volume": "89","pages": "473--484", "doi" : "10.1016/j.euromechflu.2021.07.003", "bibtexKey": "Baumann_2021" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/28a43e01d848ee7c63972db59621f5ce4/bjoern_dick", "tags" : [ "CFD","Node-level","Performance","optimizations" ], "intraHash" : "8a43e01d848ee7c63972db59621f5ce4", "interHash" : "e2508a1757d2e62addf22ba7678550d7", "label" : "Node-level Performance Optimizations in CFD Codes", "user" : "bjoern_dick", "description" : "", "date" : "2021-08-03 12:59:18", "changeDate" : "2021-08-03 10:59:18", "count" : 1, "pub-type": "inproceedings", "booktitle": "HPC Asia 2021: The International Conference on High Performance Computing in Asia-Pacific Region Companion","publisher":"Association for Computing Machinery, New York, NY, United States", "year": "2021", "url": "", "author": [ "Peter Wauligmann","Jakob Dürrwächter","Philipp Offenhäuser","Adrian Schlottke","Martin Bernreuther","Björn Dick" ], "authors": [ {"first" : "Peter", "last" : "Wauligmann"}, {"first" : "Jakob", "last" : "Dürrwächter"}, {"first" : "Philipp", "last" : "Offenhäuser"}, {"first" : "Adrian", "last" : "Schlottke"}, {"first" : "Martin", "last" : "Bernreuther"}, {"first" : "Björn", "last" : "Dick"} ], "pages": "7-8", "isbn" : "978-1-4503-8303-5", "eventdate" : "January 20-22, 2021", "eventtitle" : "HPC Asia 2021: The International Conference on High Performance Computing in Asia-Pacific Region", "bibtexKey": "wauligmann2021nodelevel" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/21117089d11a61edf426da44c62d5c1e7/amgad.dessoky", "tags" : [ "Aerodynamics","CFD","Energy","Momentum","VAWT" ], "intraHash" : "1117089d11a61edf426da44c62d5c1e7", "interHash" : "5019e4aae28426be260e637e59fdf16f", "label" : "Accuracy and consistency of CFD and engineering models for simulating vertical axis wind turbine loads", "user" : "amgad.dessoky", "description" : "", "date" : "2021-07-15 18:32:28", "changeDate" : "2021-07-15 16:32:28", "count" : 2, "pub-type": "article", "journal": "Energy","publisher":"Elsevier", "year": "2020", "url": "", "author": [ "Galih Bangga","Amgad Dessoky","Zhenlong Wu","Krzysztof Rogowski","Martin OL Hansen" ], "authors": [ {"first" : "Galih", "last" : "Bangga"}, {"first" : "Amgad", "last" : "Dessoky"}, {"first" : "Zhenlong", "last" : "Wu"}, {"first" : "Krzysztof", "last" : "Rogowski"}, {"first" : "Martin OL", "last" : "Hansen"} ], "volume": "206","pages": "118087", "bibtexKey": "bangga2020accuracy" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/25952107775fa7faba4902192901d876e/h.vijayakumaran", "tags" : [ "biomimetic","cfd","hydrofoil","myown","propulsion","vorticity" ], "intraHash" : "5952107775fa7faba4902192901d876e", "interHash" : "35479099edd146890a2e688fa19f56b2", "label" : "Experimental and numerical study of penguin mode flapping foil propulsion system for ships", "user" : "h.vijayakumaran", "description" : "", "date" : "2020-07-20 16:15:26", "changeDate" : "2020-07-20 14:15:26", "count" : 1, "pub-type": "article", "journal": "Journal of Bionic Engineering","publisher":"Springer", "year": "2017", "url": "", "author": [ "Naga Praveen Babu Mannam","Parameswaran Krishnankutty","Harikrishnan Vijayakumaran","Richards Chizhuthanickel Sunny" ], "authors": [ {"first" : "Naga Praveen Babu", "last" : "Mannam"}, {"first" : "Parameswaran", "last" : "Krishnankutty"}, {"first" : "Harikrishnan", "last" : "Vijayakumaran"}, {"first" : "Richards Chizhuthanickel", "last" : "Sunny"} ], "volume": "14","number": "4","pages": "770--780", "bibtexKey": "mannam2017experimental" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/29fd8efb4f6b0c0d07fe9cf211366c3f9/h.vijayakumaran", "tags" : [ "biomimetic","cfd","hydrofoil","myown","propulsion","vorticity" ], "intraHash" : "9fd8efb4f6b0c0d07fe9cf211366c3f9", "interHash" : "1d59d69d2658c554d08ca09769ae7476", "label" : "Computational fluid dynamics study of a flexible flapping hydrofoil propulsor", "user" : "h.vijayakumaran", "description" : "", "date" : "2020-07-20 16:09:14", "changeDate" : "2020-07-20 14:18:49", "count" : 1, "pub-type": "inproceedings", "booktitle": "International Conference on Offshore Mechanics and Arctic Engineering", "year": "2016", "url": "", "author": [ "Harikrishnan Vijayakumaran","Parameswaran Krishnankutty" ], "authors": [ {"first" : "Harikrishnan", "last" : "Vijayakumaran"}, {"first" : "Parameswaran", "last" : "Krishnankutty"} ], "volume": "49934","pages": "V002T08A005", "bibtexKey": "vijayakumaran2016computational" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2a5b50b70d56ad06493256e3ecae59fa1/annettegugel", "tags" : [ "Behaviour","CFD","Measurements","Thermal","Transformers","Validation" ], "intraHash" : "a5b50b70d56ad06493256e3ecae59fa1", "interHash" : "f03c4f887c75eb877fa83224457e1a98", "label" : "Investigation of the Thermal Behaviour of Transformers by CFD and Validation by\r\nMeasurements", "user" : "annettegugel", "description" : "", "date" : "2020-06-24 14:54:12", "changeDate" : "2020-06-24 12:57:46", "count" : 1, "pub-type": "proceedings", "year": "2010", "url": "", "author": [ "Andreas Weinläder","Stefan Tenbohlen" ], "authors": [ {"first" : "Andreas", "last" : "Weinläder"}, {"first" : "Stefan", "last" : "Tenbohlen"} ], "eventtitle" : "3rd International Advanced Research Workshop on Transformers", "venue" : "Santiago de Compostela, Spain", "eventdate" : "October 4-6", "bibtexKey": "weinlader2010investigation" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/235a9e5873c798f734d49f74116c5978f/annettegugel", "tags" : [ "CFD","Distribution","Flow","Oil","Power","Temperature","Transformers" ], "intraHash" : "35a9e5873c798f734d49f74116c5978f", "interHash" : "17bdadaed9e1e6dae1d8e98fb14f72eb", "label" : "Prediction of the Oil Flow and Temperature Distribution in Power Transformers by\r\nCFD", "user" : "annettegugel", "description" : "", "date" : "2020-06-23 15:35:53", "changeDate" : "2020-06-23 13:36:53", "count" : 1, "pub-type": "conference", "year": "2010", "url": "", "author": [ "Andreas Weinläder","Stefan Tenbohlen","R. Wittmaack" ], "authors": [ {"first" : "Andreas", "last" : "Weinläder"}, {"first" : "Stefan", "last" : "Tenbohlen"}, {"first" : "R.", "last" : "Wittmaack"} ], "eventtitle" : "CIGRE Session", "venue" : "Paris, France", "eventdate" : "August 22-27", "bibtexKey": "weinlader2010prediction" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/242843ca5eb4e733f03adbe0544f79d57/annettegugel", "tags" : [ "CFD","Distribution","Flow","Modelling","Network","Oil","Oil-immersed","Transformer","Windings" ], "intraHash" : "42843ca5eb4e733f03adbe0544f79d57", "interHash" : "77d88e667635065f9f5c0c81f133d36c", "label" : "Prediction of the Oil Flow Distribution in Oil-immersed Transformer Windings by\r\nNetwork Modelling and CFD", "user" : "annettegugel", "description" : "", "date" : "2020-06-15 15:50:05", "changeDate" : "2020-06-15 13:50:05", "count" : 1, "pub-type": "article", "journal": "IET Electric Power Applications", "year": "2011", "url": "", "author": [ "Andreas Weinläder","W. Wu","Stefan Tenbohlen","Z. Wang" ], "authors": [ {"first" : "Andreas", "last" : "Weinläder"}, {"first" : "W.", "last" : "Wu"}, {"first" : "Stefan", "last" : "Tenbohlen"}, {"first" : "Z.", "last" : "Wang"} ], "bibtexKey": "weinlader2011prediction" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2b463581b194b0abc0c7108e55cb57c3b/itlr", "tags" : [ "FEA","coupling","from:alexschindler","CFD","myown","vonwolfersdorf","heat_transfer","transient","conjugate" ], "intraHash" : "b463581b194b0abc0c7108e55cb57c3b", "interHash" : "05ce810d0af9774460c8cec32dece001", "label" : "Coupled FE-CFD Analysis of Transient Conjugate Heat Transfer", "user" : "itlr", "description" : "", "date" : "2020-01-21 15:19:16", "changeDate" : "2020-01-21 14:19:16", "count" : 2, "pub-type": "conference", "year": "2019", "url": "https://www.euroturbo.eu/publications/proceedings-papers/etc2019-158/", "author": [ "Alexander Schindler","Stefan Brack","Jens von Wolfersdorf" ], "authors": [ {"first" : "Alexander", "last" : "Schindler"}, {"first" : "Stefan", "last" : "Brack"}, {"first" : "Jens", "last" : "von Wolfersdorf"} ], "eventtitle" : "13th European Conference on Turbomachinery Fluid dynamics & Thermodynamics", "venue" : "Lausanne, Switzerland", "bibtexKey": "schindler2019coupled" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/2b463581b194b0abc0c7108e55cb57c3b/alexschindler", "tags" : [ "CFD","FEA","conjugate","coupling","heat_transfer","myown","transient","vonwolfersdorf" ], "intraHash" : "b463581b194b0abc0c7108e55cb57c3b", "interHash" : "05ce810d0af9774460c8cec32dece001", "label" : "Coupled FE-CFD Analysis of Transient Conjugate Heat Transfer", "user" : "alexschindler", "description" : "", "date" : "2020-01-20 13:41:43", "changeDate" : "2020-01-21 14:19:16", "count" : 2, "pub-type": "conference", "year": "2019", "url": "https://www.euroturbo.eu/publications/proceedings-papers/etc2019-158/", "author": [ "Alexander Schindler","Stefan Brack","Jens von Wolfersdorf" ], "authors": [ {"first" : "Alexander", "last" : "Schindler"}, {"first" : "Stefan", "last" : "Brack"}, {"first" : "Jens", "last" : "von Wolfersdorf"} ], "eventtitle" : "13th European Conference on Turbomachinery Fluid dynamics & Thermodynamics", "venue" : "Lausanne, Switzerland", "bibtexKey": "schindler2019coupled" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/20669e82b0543faeba63ffb6a6b771bc0/saeed_khndn99", "tags" : [ "Affecting","CFD","Thermal" ], "intraHash" : "0669e82b0543faeba63ffb6a6b771bc0", "interHash" : "d9ec57731236119ebce18d62db15df93", "label" : "Investigation of Operational and Design Parameters Affecting the Thermal Behaviour of Disc-Type Winding", "user" : "saeed_khndn99", "description" : "", "date" : "2019-09-03 15:45:42", "changeDate" : "2019-09-03 14:31:11", "count" : 2, "pub-type": "conference", "year": "2019", "url": "", "author": [ "Saeed Khandan","Stefan Tenbohlen" ], "authors": [ {"first" : "Saeed", "last" : "Khandan"}, {"first" : "Stefan", "last" : "Tenbohlen"} ], "abstract": "The lifetime and reliability of a power transformer are highly dependent on the lifetime of its insulation. Since excessive heat generation is the major cause of deteriorating insulation and aging, an optimal cooling design is necessary to avoid operating faults and material degradation. In this contribution, significant operational and geometrical parameters are considered and analyzed to predict their influences on the thermal behavior inside an oil-directed cooled winding model. This study presents 3D numerical Computational Fluid Dynamics results to determine the hot-spot temperature and its location by applying various boundary conditions, which are validated with measured temperatures from an experimental setup. The experimental setup consists of an oil feeding unit and a winding model consisting of 20 discs, which is equipped with fluid guides to obtain a zig-zag cooling mode. To account for the variations of the thermal characteristics of oil, its properties are changed by increasing the inlet oil temperature. The geometrical parameters can be divided into horizontal cooling channel height, vertical cooling channel width and number of discs per pass; whereas main operating parameters consist of inlet flow rate, inlet oil temperature and heat losses. The temperature profiles illustrate that reducing the height of horizontal channels, apart from making the transformer smaller, decreases the blockage caused by flow eddies and improves the oil flow distribution. Moreover, while the presence of fewer discs between two successive fluid guides aids in decreasing hot-spot and average oil temperature, it also leads to an increased drop in oil pressure. These results can be applied to optimize cooling aspects of disc-type windings.", "eventtitle" : "International Symposium on High Voltage Engineering, ISH 2019", "venue" : "Budapest, Hungary", "eventdate" : "26-30 August 2019", "bibtexKey": "noauthororeditor" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/27b2b902302365aeebb4e3f454f7a5335/ieh", "tags" : [ "from:annettegugel","CFD","Investigation" ], "intraHash" : "7b2b902302365aeebb4e3f454f7a5335", "interHash" : "92406c660269dc428f3f9d977f12b945", "label" : "CFD Investigation of Temperature Distributions by Non-uniform Heat Losses inside Windings", "user" : "ieh", "description" : "", "date" : "2019-06-13 13:42:37", "changeDate" : "2024-10-28 09:53:04", "count" : 3, "pub-type": "conference", "year": "2018", "url": "", "author": [ "Saeed Khandan","Stefan Tenbohlen" ], "authors": [ {"first" : "Saeed", "last" : "Khandan"}, {"first" : "Stefan", "last" : "Tenbohlen"} ], "eventtitle" : "2018 IEEE International Conference on High Voltage Engineering and Application (ICHVE 2018)", "venue" : "Athens, Greece", "eventdate" : "September 10-13", "bibtexKey": "khandan2018investigation" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/29657413b6cfa576171be427a282117fc/fabianmeyer", "tags" : [ "cfd","ians","uq" ], "intraHash" : "9657413b6cfa576171be427a282117fc", "interHash" : "2ae16f8404bf213482895b33b375e7d1", "label" : "Uncertainty Quantification for Direct Aeroacoustic Simulations of\r\n\tCavity Flows", "user" : "fabianmeyer", "description" : "", "date" : "2018-10-23 10:04:08", "changeDate" : "2018-10-23 08:04:08", "count" : 2, "pub-type": "article", "year": "2018", "url": "https://doi.org/10.1142/S2591728518500445", "author": [ "T. Kuhn","J. Dürrwächter","A. Beck","C.-D. Munz","F. Meyer","C. Rohde" ], "authors": [ {"first" : "T.", "last" : "Kuhn"}, {"first" : "J.", "last" : "Dürrwächter"}, {"first" : "A.", "last" : "Beck"}, {"first" : "C.-D.", "last" : "Munz"}, {"first" : "F.", "last" : "Meyer"}, {"first" : "C.", "last" : "Rohde"} ], "volume": "Journal of Theoretical and Computational Acoustics","abstract": "We investigate the influence of uncertain input parameters on the\r\n\taeroacoustic feedback of cavity flows. The so-called Rossiter feedback\r\n\trequires a direct numerical computation of the acoustic noise, which\r\n\tsolves hydrodynamics and acoustics simultaneously, in order to capture\r\n\tthe interaction of acoustic waves and the hydrodynamics of the flow.\r\n\tDue to the large bandwidth of spatial and temporal scales, a high\r\n\torder numerical scheme with low dissipation and dispersion error\r\n\tis necessary to preserve important small scale information. Therefore,\r\n\tthe open-source CFD solver FLEXI, which is based on a high-order\r\n\tdiscontinuous Galerkin spectral element method, is used to perform\r\n\tthe aforementioned direct simulations of an open cavity configuration\r\n\twith a laminar upstream boundary layer. \r\n\t\r\n\tTo analyse the precision of the deterministic cavity simulation with\r\n\trespect to random input parameters we establish a framework for uncertainty\r\n\tquantification. In particular, a non-intrusive spectral projection\r\n\tmethod with Legendre and Hermite polynomial basis functions is employed\r\n\tin order to treat uniform and normal probability distributions of\r\n\tthe uncertain input. The results indicate a strong, non-linear dependency\r\n\tof the acoustic feedback mechanism on the investigated uncertain\r\n\tinput parameters. An analysis of the stochastic results offers new\r\n\tinsights into the noise generation process of open cavity flows and\r\n\treveals the strength of the implemented uncertainty quantification\r\n\tframework.", "owner" : "meyerfn", "doi" : "10.1142/S2591728518500445", "bibtexKey": "kuhn2018uncertainty" } , { "type" : "Publication", "id" : "https://puma.ub.uni-stuttgart.de/bibtex/229f749fa799452a021ec4ec0e1824599/lisaba", "tags" : [ "CFD","Modellierung","Turbulenz" ], "intraHash" : "29f749fa799452a021ec4ec0e1824599", "interHash" : "2159a1dff2b9186c4a8b2bdae7b2df07", "label" : "An introduction to computational fluid dynamics : the finite volume method", "user" : "lisaba", "description" : "", "date" : "2018-09-06 12:13:37", "changeDate" : "2018-09-06 10:13:37", "count" : 1, "pub-type": "book", "publisher":"Pearson/Prentice Hall","address":"Harlow; Munich", "year": "2010", "url": "http://www.worldcat.org/search?qt=worldcat_org_all&q=9780131274983", "author": [ "Henk K. Versteeg","W. Malalasekera" ], "authors": [ {"first" : "Henk K.", "last" : "Versteeg"}, {"first" : "W.", "last" : "Malalasekera"} ], "isbn" : "9780131274983 0131274988", "refid" : "700639594", "bibtexKey": "versteeg2010introduction" } ] }