Sökning: "direct numerical simulation DNS"

Visar resultat 1 - 5 av 37 avhandlingar innehållade orden direct numerical simulation DNS.

  1. 1. Droplet growth in atmospheric turbulence : A direct numerical simulation study

    Författare :Xiang-Yu (李翔宇) Li; Gunilla Svensson; Axel Brandenburg; Wojciech Grabowski; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cloud micro-physics; turbulence; inertial particles; DNS; condensation; collision; coalescence; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography;

    Sammanfattning : This Ph.D. thesis examines the challenging problem of how turbulence affects the growth of cloud droplets in warm clouds. Droplets grow by either condensation or collision. LÄS MER

  3. 2. Combustion characteristics of some alternative fuels in ICE: : a detailed numerical study

    Författare :Siyuan Hu; Strömningsteknik; []
    Nyckelord :Combustion; duel fuel; methane; hydrogen; nheptane; methanol; DNS; simulation; openFoam; mixture-averaged; RCCI; ignition wave;

    Sammanfattning : Two major fuels commonly used in compression ignition (CI) and spark ignition (SI) enginesare diesel and gasoline. The reserve of diesel and gasoline is limited, however the combustion ofthese fuels giving rise to air pollution. LÄS MER

  4. 3. Direct numerical simulation of turbulent premixed flames at high Karlovitz numbers: structure and modelling

    Författare :Thommie Nilsson; Strömningsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct numerical simulation; Computational fluid dynamics; Combustion model; Premixed flame; Turbulence; Karlovitz number;

    Sammanfattning : There has been recent increased interest in premixed flames and in particular for use in gas turbines for power generation. This is a development that follows from increasing demands for high efficiency and low emissions of NOx, which can be achieved by using premixed flames and lean pre-heated mixtures, often close to the lean flammability limit. LÄS MER

  5. 4. Fundamental studies of non-premixed combustion in turbulent wall jets using direct numerical simulation

    Författare :Zeinab Pouransari; V. Arne Johansson; Christer Fureby; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulence; non-premixed combustion; global reaction; direct numerical simulation; wall-jet; heat release; mixing scales; heat transfer; Other engineering mechanics; Övrig teknisk mekanik;

    Sammanfattning : The present thesis deals with the fundamental aspects of turbulent mixingand non-premixed combustion in wall-jet flows. Direct numerical simulations(DNS) of compressible turbulent flows are performed in a wall-jet configura-tion, which has a close resemblance to many industrial combustion applica-tions. LÄS MER

  7. 5. Transition delay in boundary-layer flows via reactive control

    Författare :Nicolò Fabbiane; Dan S. Henningson; Shervin Bagheri; Denis Sipp; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow control; drag reduction; net energy saving; adaptive control; model-based control; optimal control; flat-plate boundary layer; laminar-to- turbulent transition; plasma actuator; direct numerical simulation; in-flight experiments; strömningsstyrning; friktionsreduktion; netto energibesparing; adaptiv styrning; modellbaserad styrning; optimal kontroll; gränsskikt öve en plan platta; laminärt till turbulent omslag; plasma aktuator; DNS; flyg prov; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : Transition delay in boundary-layer flows is achieved via reactive control of flow instabilities, i.e. Tollmien-Schlichting (TS) waves. Adaptive and model-based control techniques are investigated by means of direct numerical simulations (DNS) and experiments. LÄS MER