To uilize the shallow geothermal energy, heat pumps are often coupled with borehole heat exchangers (BHE) for heating and cooling buildings. In cold regions, soil freezing around the BHE is a potential problem which can seriously influence the underground soil temperature distribution, inlet and outlet fluid temperature of the BHE, and thus the efficiency of the whole GSHP system. The influence of the freezing process on the overall system performance is investigated by comparing different BHE configuration with and without latent heat effect from the frozen groundwater. The coefficient of performance (COP) of the heat pump will alter when freezing process in taken into account and lead to various electricity consumption. Except for the efficiency aspect, the freezing behavior can also lead to the redistribution of pore pressure and fluid flow, and in some extreme cases can even result in frost damage to the BHEs. A fully coupled thermohydro-mechanical model is required for advanced system design and scenario analyses. Based on the framework of the Theory of Porous Media, a triphasic freezing model is derived and solved with the finite element method. Ice formation in the porous medium results from a coupled heat and mass transfer problem with phase transition and is accompanied by volume expansion. The model is able to capture various coupled physical phenomena through the freezing process including the latent heat effect, groundwater flow with porosity change and mechanical deformation. With this kind of THM freezing model, we are also able to solve different kinds of engineering problem, e.g. geotechnics, construction engineering and material engineering.

With increasing interest in utilizing the inland waterways (IWW) in European countries, the design of IWW vessels gains attention both from a transport efficiency and an emission control point of view. However, unlike in western and central European countries, in Nordic countries, e.g. Sweden, IWW ships must deal with ice on the fairway during every winter. Usually, IWW ships are designed without ice concerns and are structurally weaker compared to ships designed according to ice class notification from the classification societies. Developing such ships requires particular concerns since there is no strict requirements regarding ice class notifications for IWW ships. A primary challenge is to estimate both the global and local ice loads acting on the ship hull structure. To consolidate the design problems for IWW ice-going ships, Lake Mälaren is selected. Ice conditions, i.e. ice type and concentration, and ice data, e.g. ice thickness and ice flexural strength, are extracted and analysed for the ice load estimation. The ice mechanical properties have great influence on the ice load. Ice characteristics are studied based on empirical formulae and properties are calibrated by reference data. The deterministic approach is widely used to predict the ice loads. It is suitable when all variables, i.e. ship geometry and ice properties, are known and refers to rule-based design hereby. For first year light ice conditions in Lake Mälaren, the Finnish Swedish Ice Class Rule (FSICR) is widely used. The thesis uses guidelines from the Finnish Swedish Ice Class Rules as a reference and compare the results with other methods. The probabilistic approach, on contrary, is useful when certain variables are unknow, which are interpreted as random variables, for instance ice breaking pattern. Here the probabilistic method and ice-hull interaction mechanism are studied. The probabilistic method simplifies the ice pressure in relation to the contact area between the ice and the ship hull. It predicts maximum ice pressure acting on the ship hull based on field ice test data and ice exposure conditions. Such semi-empirical method can be used regardless of ship type and size. For this, a numerical model is introduced based on ice-hull collision mechanisms and the essential ice breaking characteristics. The physical mechanism is studied for idealizing ship-ice impact model. The idealization model includes the ice failure process, ice conditions and ship geometry. The ice failure is assumed to be initiated by crushing ice and followed by breaking due to bending failure. Ice properties are set as constant values without any variations. The stochasticity in interact process is represented by randomness in collision location and number of pieces of ice floe formed after breaking. An energy method is used to calculate the ice crushing force, indentation displacement and contact area. The ice bending scenario is simplified as an infinite plate resting on an elastic foundation under a concentrated load. Ice impact load and critical load can be obtained for global and local structural assessment respectively. The structural responses and structural strength of a representative panel at linear and nonlinear contexts are investigated as well. Ship structure is commonly designed with material yield strength as limit. However, the study shows a lighter structure can be achieved if plastic deformation is allowed without causing failure. Therefore, the design can be optimized with regards to ice loading capacity and weight control.

This report details the work done in a master thesis project. The project was conducted at the Brake Performance Department at Scania CV AB. The project involves the development of a numerical model (in Matlab) that calculates and predicts air consumption in a truck under different drive cycles. The report first details tests and experiments done so as to acquire the necessary information for the development of the model. The report then presents the model that was created and delves into tests that were conducted for its validation. A model is created that allows the user to select different component combinations on the trucks along with different loading scenarios and drive cycles. Finally the model is used to evaluate air consumption in trucks during particularly strenuous cycles. The model developed is found to be reliable and accurate to with 7% with regard to amount of air consumed. With its help, several recommendations on how air consumption in commercial vehicles can be improved are made. The best components’ combination is also found and presented. / I denna rapport beskrivs ett examensarbete som genomfördes på bromsavdelningen på Scania CV AB. Projektet innefattar utveckling av en numerisk modell (i Matlab) som beräknar och förutspår luftförbrukningen i en lastbil under olika körcykler. I rapporten beskrivs det tester och experiment som gjordes för att ta fram nödvändiga uppgifter för utvecklingen av modellen. Sedan presenteras modellen som skapades och alla valideringstester som genomfördes. Modellen är gjord så att användaren kan kombinera olika komponentkombinationer för lastbilar med olika lastningskonfigurationer och körcykler. Slutligen används modellen för att utvärdera luftförbrukningen i lastbilar under särskilt ansträngande körcykler. Den utvecklade modellen visade sig vara pålitlig och korrekt med en felmarginal på 7% med avseende på mängden luft som konsumeras. Med dess hjälp kunde flera rekommendationer ges om hur luftförbrukningen i kommersiella fordon kan förbättras. De bästa komponentkombinationerna hittades också och presenteras i denna rapport

A variation on a numerical model of the motor protein myosin V presentedin a paper by Craig and Linke (2009) is developed. An alternative potential is proposed. All aspects of the model development arederived in detail and tested. Two model tests are created and used toconfirm the correctness of the developed model. A simulation demonstratesthat the developed model is able to produce a myosin V step. Adidactical transposition is presented in the form of a compendium, in which a numerical model of myosin V by Craig and Linke (2009) isdescribed. The didactical transposition is developed using a methodologyof didactical engineering. The didactical study indicated thatthe content was well recieved by the target group of eight individualsin respect to the scientific complexity and that it evokes motivation forlearning. The study also indicated that unsuccessful areas of the didacticaltransposition existed. / En variation av en numerisk modell av motorproteinet myosin V presenteradav Craig och Linke (2009) utvecklas. En alternativ potential föreslås. Alla aspekter av modellutvecklingen härleds i detalj och testas.Två modelltester skapas och används för att bekräfta riktigheteni den utvecklade modellen. En simulering demonstrerar att myosin Vkan ta ett steg i den utvecklade modellen.En didaktisk transposition presenteras i form av ett kompendium,där en numerisk modell av myosin V av Craig och Linke (2009) beskrivs.Metodologiskt utvecklas den didaktiska transpositionen medhjälp av didaktisk ingenjörskonst. Den didaktiska studien indikeradeatt innehållet togs emot väl av målgruppen bestående av åtta personeri hänseende till vetenskaplig komplexitet och att det väckte motivationför lärande. Studien indikerade även att misslyckade områden av dendidaktiska transpositionen förekom.

Microwave curing has become a trend in composite processing due to its efficiency in energy consumption compared to the traditional curing method. However, as commonly found in every composite processing, controlling the microwave curing process remains challenging. The most feasible control method is to build a numerical model. In this report, the numerical model was developed to simulate the microwave heating of cured and uncured glass/epoxy samples. The objective of cured sample simulation was to obtain the average electric field intensity generated in the composite, which was then used in the uncured sample simulation. Meanwhile, three methods of microwave heating to the uncured samples were suggested, i.e. heating with constant electric field intensity, heating with non-constant electric field intensity, and heating with concentrated electric field intensity. The simulation was further expanded by combining microwave heating with contact heating to improve the curing state on the corner section. The simulation showed a reasonable temperature evolution trend for all three microwave-heated methods of an uncured sample. However, they are all different from the experiment result. Meanwhile, a high temperature in the core layer was observed in all simulations with a gradual temperature decline toward the outer layer, as expected from a microwave heated object. Finally, a decent degree of cure was obtained by employing additional contact heating without involving microwaves. / Mikrovågsbaserad härdning har blivit en trend inom komposittillverkning på grund av dess energieffektivitet jämfört med den traditionella härdningsmetoden. Men precis som i all komposittillverkning är det fortfarande utmanande att kontrollera mikrovågshärdningsprocessen. Den mest genomförbara kontrollmetoden är att bygga en numerisk modell. I den här rapporten utvecklades en numerisk modell för att simulera mikrovågvärmning av härdat och ohärdat glas/epoxiprover. Målet med simuleringen av de härdade proven var att få fram den genomsnittliga intensiteten av det elektriska fältet som genereras i kompositen, vilket sedan användes i simuleringen av de ohärdade proven. Samtidigt föreslogs tre metoder för mikrovågshärdning av de ohärdade proven, nämligen uppvärmning med konstant intensitet av det elektriska fältet, uppvärmning med varierande intensitet av det elektriska fältet och uppvärmning med koncentrerad intensitet av det elektriska fältet. Simuleringen utökades sedan genom att kombinera mikrovågshärdning med kontaktuppvärmning för att förbättra härdningsgraden i hörnsektionen. Simuleringen visade en rimlig temperaturutveckling för alla tre metoder för mikrovågsuppvärmda ohärdade prov. Dock skiljer de sig alla från experimentresultatet. Samtidigt observerades en hög temperatur i kärnskiktet i alla simuleringar med gradvis temperatursänkning mot ytterlagret, vilket förväntas hos ett mikrovågsuppvärmt objekt. Slutligen uppnåddes en acceptabel härdningsgrad genom mot sluret addera kontaktuppvärmning utan mikrovågor.

The presence of vegetation in open channel flow has a significant influence on flow resistance, turbulence structures and sediment transport. This study will evaluate flow resistance and scale velocity profile in depth limited flow conditions, specifically investigating the impact of vegetation on the flow resistance under submerged flow conditions. The resistance induced by vegetation in open channel flows has been interpreted differently in literature, largely due to different definitions of friction factors or drag coefficients and the different Reynolds numbers. The methods utilized in this study are based on analytical and numerical models to investigate the effects of vegetation presence on flow resistance in open channel flows. The performing strategy approach was applied by three-dimensional computational fluid dynamics (CFD) simulations, using artificial cylinders for the velocity profile. This is to estimate the average flow velocity and resistance coefficients for flexible vegetation, which results in more accurate flow rate predictions, particularly for the case of low Reynolds number. This thesis shows different formulas from previous studies under certain conditions for a length scale metric, which normalises velocity profiles of depth limited open channel flows with submerged vegetation, using both calculated and simulated model work. It considers the submerged vegetation case in shallow flows, when the flow depth remains no greater than twice the vegetation height. The proposed scaling has been compared and developed upon work that have been influenced by logarithmic and power laws to present velocity profiles, in order to illustrate the variety of flow and vegetation configurations.

No description available.

The underlying motives of the research undertaken here are twofold: to obtain a deeper understanding of the dewatering mechanisms at the forming section of a papermaking machine and to develop numerical models that describe the flow through forming fabrics. More comprehensive knowledge of dewatering in the forming section allows suggestions to be made for improvements that reduce the amount of energy used in the process without affecting the quality of the end product.   The objective of this thesis is to answer the following questions: How and why does rewetting occur at the high vacuum suction boxes? How does the structure of the forming fabric affect dewatering at the forming section? Is it possible to create accurate numerical models for forming fabrics, and can these be used to predict the dewatering behaviour of new types of fabrics?   Laboratory and pilot studies simulating high vacuum suction boxes were performed together with numerical modelling of the flow of air and water through both the forming fabric and the paper sheet.   The conclusion drawn from the pilot study is that rewetting significantly lowers the dryness of the paper sheet exiting the suction boxes. The phenomenon is extremely rapid and is most likely driven by capillary forces. The high speed at which this rewetting occurs makes it difficult to impede by placing the suction boxes closer to the couch pick-up: the solution is more likely to be the use of new and improved designs of the forming fabric. The structure of the forming fabric has been shown to affect the dewatering rate at certain conditions of vacuum dewatering, and can possibly be connected partly to the fact that fibres penetrate the surface of the fabric to varying degrees and partly to the flow resistance of the different fabric structures. Numerical models of high accuracy can be constructed and used to predetermine how new fabric designs would affect dewatering at the forming section.   This thesis quantifies aspects of dewatering such as rewetting and the influence of the forming fabric. Understanding these dewatering aspects further provides for the potential enhancement of energy efficiency in the forming section, and thereby the entire papermaking process. The forming fabric can play an important role in improving energy efficiency: rewetting after the high vacuum suction boxes occurs more rapidly than was previously known, so its design might be the only possible way of impeding it. The forming fabric can also improve the rate of dewatering: it is therefore likely that its design will be important in the next stage of developing energy efficiency and thereby play a part in achieving a more sustainable future. / This thesis quantifies aspects of dewatering such as rewetting and the influence of the forming fabric. Understanding these dewatering aspects further provides for the potential enhancement of energy efficiency in the forming section, and thereby the entire papermaking process. The forming fabric can play an important role in improving energy efficiency: rewetting after the high vacuum suction boxes occurs more rapidly than was previously known, so its design might be the only possible way of impeding it. The forming fabric can also improve the rate of dewatering: it is therefore likely that its design will be important in the next stage of developing energy efficiency and thereby play a part in achieving a more sustainable future.

The diploma thesis deals with the proposal of measures on the Svratka stream in the cadastral area Český Herálec and Herálec na Moravě. The aim of the diploma thesis is to propose appropriate flood protection in the Herálec urban area and to elaborate proposals of nature friendly measures outside the municipality’s built up area, which will enable the renewal of the ecological functions of Svratka in the spring area. In the diploma thesis the assessment of the current state of the watercourse in the analyzed locality was caried out and also the assessment of the capacity of the watercourse and the objects on there. Furthermore, the flood levels and its areas were determined. Hydraulic water flow calculations were performed using the 1D and 1D/2D numerical model. For calculation, HEC-RAS 5.0.3 was used. When processing a 1D/2D numerical model, a manual describing the progress of work in the HEC-RAS 5.0.3 program was also created. On the basis of the results from the numerical model, a proposal for flood protection measures in the urban area and nature friendly measures in the extravilan was carried out.

Recently observed cumulation of unexpected collapses of slope-distant waste dumps in lignite mining areas of eastern germany re-initiated research of soil liquefaction. Especially it turned the question of internal initials that correspond to water rise. Parallel to laboritory tests and field experiments a micromechanical model should be developed, which can reproduce processes in the soil during saturation. In first approximation a partly saturated soil consists of two phases: the soil particles and the pore fluid. For micromechanical modeling a coupling of discontinuum particles) and continuum (fluid) is required. The soil particles can be simulated with the Discrete-Element-Method (DEM). For the pore fluid, which is assumed to be a mixture of liquid and gaseous fractions, Pore scale model with Finite Volumes (PFV) is used. At low water content liquid bridges (meniscii) arise between the particles that cause an apparent cohesion. The effect of the meniscii is considered by a correspondingly contact law in the DEM model. During the saturation of a soil both, cohesive effect and fluid bulk modulus, are reduced. In addition buoyancy acts on the particles during the process. The micromechanical modeling approach has the advantage, that just a few model parameters are needed. The numerical model shows pore fluid pressures during saturation process, that leads to a reduction of effective stress. It is investigated how much the reduction is regarding porosity, degree of saturation, stress conditions and grain shape. Furthermore the influence of model parameters as well as hydromechanics is investigated. The investigations are completed with another series of experiments under special conditions like integration of macropores, horizontal fixed model boundaries and abrupt saturation.