Particle-laden flows involve in many energy and industrial processes within a wide scale range. Solid fuel combustion and gasication, drying and catalytic cracking are some of the examples. It is vital to have a better understanding of the phenomena inside the reactors involving in particle-laden flows for process improvements and design. Computational fluid dynamics (CFD) can be a robust tool for these studies with its advantage over experimental methods. The large variation of length scales (101- 10-9 m) and time scales (days-microseconds) is a barrier to execute detailed simulations for large scale reactors. Current state-of-the-art is to use models to bridge the gap between small scales and large scales. Therefore, the accuracy of the models is key to better predictions in large scale simulations.    Particle-laden flows have complexities due to many reasons. One of the main challenge is to describe how the particle-fluid interaction varies when the particles are reacting. Particle and the fluid interact through mass, momentum and heat exchange. Mass, momentum and heat exchange is presented by the Sherwood number (Sh), drag coefficient (CD) and Nusselt number (Nu) in fluid dynamics. Currently available models do not take into account for the effects of net gas flow generated by heterogeneous chemical reactions. Therefore, the aim of this research is to propose new models for CD and Nu based on the flow and temperature fields estimated by particle-resolved direct numerical simulations (PR-DNS). Models have been developed based on physical interpretation with only one fitting parameter, which is related to the relationship between Reynolds number and the boundary layer thickness. The developed models were compared with the simulation results solving intra-particle flow under char gasification. The drawbacks of models were identied and improvements were proposed.    The models developed in this work can be used for the better prediction of flow dynamics in large scale simulations in contrast to the classical models which do not consider the effect of heterogeneous reactions. Better predictions will assist the design of industrial processes involving reactive particle-laden flows and make them highly effcient and low energy-intensive.

Syftet med den här undersökningen är att ta reda på om det finns några språkliga avvikelser från den generella skriftspråksnormen hos fotbollsjournalister på Twitter. Dessutom vill jag undersöka vilka eventuella avvikelser som förekommer samt vilka typer av eventuella språkliga förändringar som fotbollsjournalisterna vanligen gör. Detta har gjorts genom att skapa kategorier som bygger på språkliga mönster baserat på tidigare forskning. Totalt 818 twitterinlägg från åtta olika fotbollsjournalister har sedan kategoriserats. Undersökningen visar att fotbollsjournalisterna till viss del anpassar sitt språk på grund av den begränsade teckenmängden. Dessa anpassningar består huvudsakligen av förkortningar och användande av ikoner och emojis samt subjektslösa meningar. Andra språkliga drag som utrönts är att det är förhållandevis vanligt att fotbollsjournalister använder sig av en avvikande användning av skiljetecken. Vanligast av allt är dock att deras twitterinlägg inte har några större avvikelser från en generell skriftspråksnorm.

In the field of heavy-duty vehicles, fuel efficiency and environmental protection are factors that need to be focused on, while the aerodynamic drag generated during vehicle travelling is one of the most influential aspects. This thesis delves into the aerodynamic simulation of Scania trucks using the open-source Computational Fluid Dynamics (CFD) tool, OpenFOAM v2206. This study rigorously investigates the aerodynamics of two Scania truck models under different operating conditions, including scenarios with different crosswind environments at high speeds.The core of this study is to compare and analyse the computational results of OpenFOAM v2206 and its predecessor OpenFOAM v3.0+ in a number of aspects, in order to elucidate the evolution and improvement of CFD techniques and their practical impact on vehicle simulation performance. In order to save computational resources, the RANS method was used for the steady-state simulations. Preliminary comparisons were also made with results from PowerFLOW, another CFD software widely used within the Scania group.Another important part of this thesis is the exploration of an alternative meshing method (ANSA Hextreme Mesh) in CFD simulations. As a widely used pre-processing software in the Scania group today, analysing and comparing the advantages and disadvantages of ANSA and OpenFOAM in terms of meshing, such as the ease of meshing and the accuracy of aerodynamic predictions, can help to provide valuable guidance for the application of truck shape design and aerodynamic simulation.The results indicate that OpenFOAM v2206 excels in predicting aerodynamics and has utility in optimising truck design. Compared to OpenFOAM v3.0+, OpenFOAM v2206 shows smaller discrepancies in results with PowerFLOW. Further exploration is required regarding transient simulations using OpenFOAM. In terms of meshing methods, a simplified model (Allan Body) was investigated, and there is further research to be done on meshing the complete truck.In conclusion, this thesis presents a comprehensive and in-depth exploration of truck aerodynamics using advanced CFD tools. The results not only deepen the understanding of airflow dynamics around heavy vehicles, but also pave the way for the development of more aerodynamically efficient and environmentally friendly truck designs.

Difficulties exist with designing and testing on a model scale. The purpose of this study is to examine variations in the flow field of a submarine due to hull/propulsor interaction and Reynolds scaling. The scope of this study includes the simulation of the flow past a 1) five-bladed marine propeller with 0° skew, 2) unappended submarine hull, 3) forward propelled submarine with asymmetrical stern appendages, and 4) submarine in crashback with asymmetrical stern appendages. The bare hull simulations are conducted for three different length scales: small model scale, large model scale, and full scale. The isolated propeller and appended submarine simulations are conducted on the large model scale. It is of interest how sensitive the various flow characteristics are to Reynolds number and the turbulence model. All simulations are at 0° angle of attack, and validated with experimental data where available.

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