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1343 Uppsatser om Flow simulation - Sida 2 av 90
Testing and optimization of Unicorn Fluid-Structure Interaction solver for simulating an industrial problem
In industry applications, such as power supply plants, the issue of interaction between fluid and structure is always presented. More precisely, the fluid flow affects the structure by applying force(s) on it and vice versa. As a result, the structure can move (vibrate) or deform. A good understanding of this problem can help to design the system in term of safety, stability and efficiency.This project aims to optimize and test the Unicorn FSI solver from the FEniCS project [1] to simulate the interaction of fluid and structure in an experiment, which was carried out at Vattenfall Research and Development. The target is to improve the Unicorn FSI solver to cope with a real industrial problem.
Validering av vattenkraftmodeller i ARISTO
This master thesis was made to validate hydropower models of a turbine governor,Kaplan turbine and a Francis turbine in the power system simulator ARISTO atSvenska Kraftnät. The validation was made in three steps. The first step was to makesure the models was implement correctly in the simulator. The second was tocompare the simulation results from the Kaplan turbine model to data from a realhydropower plant. The comparison was made to see how the models could generatesimulation result that was similar to the reference power station.
Utvärdering och åtgärdsförslag av energianvändning i kontorsbyggnad
AbstractEmbla 5 is an office building which has done a large improvement. The clients of this building has made an order of WSP and the student Anders Kempe to calculate the use of energy for the building, and after that result proposing further measures which can decrease the energy use of Embla 5.The ground for this report is when calculation of the present energy use of the building is stated. To make that information of a number of parameters such as envelope, the heating system and ventilation has been located and set in to the simulation program IDA ICE which calculate the energy use.To improve the energy use further this project has been concentrated to change the system of ventilation. Today the ventilation system is of the kind CAV (constant air volume) and the air flow is dimensioned for after recommendations from BBR and Arbetsmiljöverket in the office spaces. Consider that Embla 5 is an office building where the people only staying for 8-10 hours/day so was the ide to see how much energy saving if the air flow is reduced the time people not being in the building.
CFD simulering av en fyrtakts Otto motorcykel motor
This thesis deals with the numerical 3D simulation of a four stroke, spark-ignited, internalcombustion engine, which is mounted on a high performance motorcycle. The work, carried outin collaboration with Politecnico di Milano and MV Agusta, focuses on the simulation of theintake, compression and expansion stroke, including combustion simulation, using an opensource CFD code.Simulation of internal combustion engines offers a great challenge in the field of CFD research.Moving boundaries of the solution domain, caused by the motion of the piston and valves, leadsto deformation of the computational grid, with decreasing quality of the solution as result. Basedon this, a previously developed mesh motion strategy was employed where a number of meshesare used to cover the whole simulation cycle. Within each mesh interval the internal cell pointsof the mesh are moved to account for the boundary motion of the piston and valves. This strategywas previously applied to simplified geometries as well as real engine geometries.
Osäkerhet i investerares avkastningsbedömning av kommersiella fastigheter. - Osäkerheter i bedömningen av drift- och underhållskostnader?
This thesis of 15 hp has been implemented at Halmstad University, in collaboration with Saab Dynamics in Linköping. Saab Dynamics is a company operating in the defence industry where competition is tough. This necessitates new ways to increase efficiency in the company, which is the basis for this thesis. Saab Dynamics wants to introduce simulation driven design. Since Saab Dynamics engineers have little experience of simulation, required a user methodology with clear guidelines.
Value-at-Risk : Historisk simulering som konkurrenskraftig beräkningsmodell
Value-at-Risk (VaR) is among financial institutions a commonly used tool for measuring market risk. Several methods to calculate VaR exists and different implementations often results in different VaR forecasts. An interesting implementation is historical simulation, and the purpose of this thesis is to examine whether historical simulation with dynamic volatility updating is useful as a model to calculate VaR and how this differs in regard to type of asset or instrument. To carry out the investigation six different models are implemented, which then are tested for statistical accuracy through Christoffersens test. We find that incorporation of volatility updating into the historical simulation method in many cases improves the model.
Modellering av rotationssystem
This master thesis was conducted during the spring of 2014 at Atlas Copco Rock Drills AB in Örebro. The purpose of the thesis was to develop a simulation model of the rotation system for a hydraulic rock drill. In the future, the model will be used to investigate the phenomena called ?jerky rotation?. In order to validate the simulation model a test bench was designed and tests were made.
Virtuellt ledarskap i näringslivet: Hur affärssimulering kan skapa kompetens, samsyn, och ökad ekonomisk förståelse i en organisation
The purpose of this thesis has been to explore the topic of business simulation from a theoretical foundation in social constructivism and theories concerning leadership as the management of meaning. The most important findings are that business simulation can be used for strategical leadership by management to create a common vision in the organisation members, which affects their perception of the business and the decisions and actions they make, which in turn can lead to a more efficient organisation that becomes better at meeting set goals. This can be viewed in different ways from different theoretical viewpoints: as inducing targeted changes in mental models to create changes in decision making and actions; as a secondary socialization process where the vision of management is externalized as a business simulation that is in turn internalized by the organisation members that participate in the business simulation, or as a way to frame and define the reality of the organisational members which creates a shared reference point against which a feeling of organisation and direction can emerge. In the future, business simulations may become increasingly used by organizations to create a common vision or to communicate a new decision to the organization members..
Modellerade och uppmätta kväveflöden i energiskog som bevattnas med avloppsvatten
The aim of this essay was to study the nitrogen flow in two willowplantations, at different locations in the south of Sweden, that wereirrigated with sewage. The study was also performed to compare thedifferences in nitrogen flows between two years, 1998 and 1999. The studywas made in three parts. First, the denitrification activity was measuredusing the acetylen inhibition method. Second the nitrogen flow, as well asthe water- and heat flows, were modeled through the SOIL-SOILN-modelThird; the nitrogen flow was calculated to compare with the results fromthe model.The results from the measurements were then compared with the resultsfrom the SOILN-simulations to detect differences in the denitrificationrate.
Implementering av Patientsimulator för Anestesimaskiner
In order to facilitate testing of anesthesia machines a patient simulator has been required by Maquet Critical Care AB. A patient simulator has been developed to reduce expensive and time consuming animal experiments and temporary lab arrangements. The patient simulator has been developed and designed to simulate human lungs with regards to anesthetic uptake, production of carbon dioxide and heating and moisturizing exhaled air.The system comprises a container and a test lung to simulate the volume and the dynamic of the human lung. The simulation of uptake of anesthetics has been implemented by pumping a fraction of the gas from the container through a bypass circuit with an active charcoal filter that adsorbs volatile anesthetics. The flow through the bypass circuit is generated by a pump and is controlled by a linear valve.The resulting performance of the patient simulator has fulfilled the requirements.
Transporttidsmodellering vid provpumpning i heterogen jord : spårämnesförsök i en isälvsavlagring
When protection zones for wells are delineated, it is important to acquire good knowledge about possible travel time from different points in the catchment area to the well. Often, simple analytical methods are used for estimating travel times and the assumption is made that the hydraulic conductivity is relatively homogenous within the aquifer. Nevertheless, many aquifers are strongly heterogeneous which may lead to differences between estimates and actual travel times. As a part of the process to develop improved methods for delineating protection zones for groundwater supply wells, a tracer experiment was performed in a glaciofluvial esker formation in Järlåsa. On the basis of the experiment, a numerical flow model was created for the test site.The purpose of this master?s thesis was to apply the flow model to an aquifer where the hydraulic conductivity shows great variability and should be described by a stochastic distribution.
Framtagning av ritplattestyrd penselsimulation för GIMP
The project was intended to produce a brush simulation plugin to the image processing program GIMP which would use a 6DOF drawing tablet for user input.Too ambitious goals coupled with compability issues between the resources used resulted in that no meaningful software was produced. Experience was however obtained, and this paper is intended to give an overview of relevant concepts for- and the process ofcreating a brush simulation..
En undersökning av VaR-modeller med Kupiecs Backtest
SAMMANDRAGHistorisk Simulation, Delta-Normal och RiskMetrics prestation utvärderas med hjälp av Kupiecs Backtest. Value at Risk (VaR) beräknas med tre olika konfidensnivåer utifrån Affärsvärldens Generalindex och HSBC kopparindex. Utifrån överträdelser från verkligt utfall undersöks vilken VaR-modell som estimerar marknadsrisken bäst. VaR-modellernas prestation jämförs, och i analysen utreds hur konfidensnivå och tillgångars egenskaper påverkar VaR-modellernas prestation. Resultaten visar att Historisk Simulation presterar bättre än Delta-Normal och RiskMetrics på den högsta konfidensnivån vilket troligtvis beror på att RiskMetrics och Delta-Normal antar normalfördelning.
Undersökning för generaliteten för lämpligt motståndarantal i Magicka ur ett flowperspektiv
Detta examensarbete undersöker skillnaden i tre olika nybörjargruppers upplevda flow då de spelat Magicka (2011) med motståndarantal som den enda skiljande variabeln. Undersökningen baseras bland annat på Csikszentmihalyis (1990) flowteori och Caillois (2001) teori om att tävlande slutar vara roligt då det urartar i kaos. Syftet med examensarbetet har varit att hitta när mest flow uppstår då nybörjare på Magicka (2011) spelar mot en viss motståndartyp, samt om detta flow bryts när för många motståndare introduceras. Undersökningen har visat att nio motståndare har resulterat i betydligt mer flow än tre, medan skillnaden mellan nio motståndare och 18 har varit obetydlig. Examensarbetet har dock inte lyckats kvantifiera var flow övergår till kaos med den testgrupp och motståndartyp som använts. Framtida forskning skulle exempelvis kunna undersöka på vilket sätt ett varierande motståndarantal skulle påverka flow för en mer erfaren testgrupp som spelar mot andra motståndartyper..
Beräkningsverktyg för plattformar till seriekompenseringsanläggningar
ABB is one of the world?s leading engineering companies in power and automation technologiesand their solutions improve performance while lowering environmental impacts for energycompanies and industries. ABB FACTS designs equipment and plants for series and phasecompensation.This thesis has been performed at ABB FACTS on the Mechanical Design (DM) department inVästerås, Sweden. The purpose of the thesis was to develop and design calculations andsimulation tools for ABB FACTS?s standard series capacitor platforms.