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Showing result 21 - 25 of 49 essays matching the above criteria.

  1. 21. Influence of grain growth on the thermal structure of inner protoplanetary discs

    University essay from Lunds universitet/Astronomi - Genomgår omorganisation; Lunds universitet/Institutionen för astronomi och teoretisk fysik - Genomgår omorganisation

    Author : Sofia Savvidou; [2018]
    Keywords : protoplanetary disc; thermal structure; hydrodynamical simulations; grain size distribution; grain growth; opacity; iceline; Physics and Astronomy;

    Abstract : Protoplanetary discs surround young stars for the first few million years after their formation and they are the birthplaces of planetary systems. The thermal structure of the discs is regulated by their dust content and the opacity that it provides. READ MORE

  3. 22. CARBONDIOXIDE FLUXES FROM A CONTROLLED BOREAL RIVER

    University essay from Mittuniversitetet/Avdelningen för ekoteknik och hållbart byggande

    Author : FRANK ARTHUR; [2018]
    Keywords : Carbon dioxide fluxes; Gas transfer Velocity; Turbulence; Eddy covariance; Stream flow; Wind speed; Global Carbon cycle; Latent and sensible heat fluxes.;

    Abstract : River, lakes and   streams account for more carbon dioxide emissions than all other freshwater   reservoirs together. However, there is still lack of knowledge of the   physical processes that control the efficiency of the air-water exchange of   CO2 in these aquatic systems. READ MORE

  4. 23. CFD Simulations of Unsteady LHA Ship Airwake in OpenFOAM

    University essay from KTH/Mekanik

    Author : Matus Cvengros; [2018]
    Keywords : ;

    Abstract : Extensive research in the past two decades has shown that flow around the sharp edges of bluff bodies, such as the superstructure of a ship, can cause large scale shear-layer separations with increased turbulence, generating a highly unsteady flow in the airwake region. Such separations affect the control margins and handling loading of a rotorcraft, mainly if operating from the vicinity of a flight deck, and therefore negatively influence the rotorcraft operating limits, which is one of the main reasons for the study of ship airwakes. READ MORE

  5. 24. Fluid motion analysis in the cryogenic tanks of the upperstage of Ariane 5 during the ascent phase

    University essay from KTH/Aerodynamik

    Author : Christophe Montsarrat; [2017]
    Keywords : ;

    Abstract : In the frame of the improvement of the performances for Ariane 5, an analysis iscarried out to explain the pressure drop observed in the ascent phase of some flights inthe liquid hydrogen (LH2) tank of the upper stage. This stage is mainly idle until therocket is out of the atmosphere but is submitted to important excitation throughoutthe ascent phase in the atmosphere. READ MORE

  6. 25. Improvement of RANS Forest Model via Closure Coefficient Modification

    University essay from Uppsala universitet/Institutionen för geovetenskaper

    Author : Geoffrey DeSena; [2017]
    Keywords : wind; turbulence; forest; model; RANS; Lopes; closure; WindSim;

    Abstract : As wind farms continue to take up more land throughout Northern Europe, developers are looking to sparsely populated areas, particularly in northern Fennoscandia, which hosts strong winds but also mixed and patchy forests over complex terrain. The complexity makes wind resource assessments difficult, raising uncertainty and therefore cost. READ MORE