Sökning: "direct numerical simulations DNS"

Visar resultat 11 - 15 av 45 avhandlingar innehållade orden direct numerical simulations DNS.

1. 11. Detailed Numerical Simulations of Turbulent Premixed Flames at Moderate and High Karlovitz Numbers

   Författare :Henning Carlsson; Strömningsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct numerical simulation; Large eddy simulation; Turbulent premixed combustion; Flow-flame interaction; High Karlovitz number;

   Sammanfattning : In generally accepted and applied flamelet combustion models, a turbulent flame is mainly assumed distorted by the large-scale turbulence eddies, whereas small-scale turbulence effects on the local flamelet structures are neglected. However, in a lot of industrial applications rather high turbulent intensities are often imposed, which induce turbulence scales at ranges smaller than the flame thickness. LÄS MER

3. 12. Numerical and experimental study of turbulent drop breakup in high­-pressure homogenizers

   Författare :Peyman Olad; Avdelningen för livsmedel och läkemedel; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; High-pressure homogenizer HPH ; Turbulent drop breakup; Computational fluid dynamics CFD ; Direct numerical simulations DNS ; Experiments;

   Sammanfattning : Emulsification is the process of making stable mixture of two or more immiscible substances (typically oil and water). The product of this process, the emulsion, is found in various applications and industries such as food (milk and other dairy products, non-dairy alternatives, mayonnaise, salad dressing), cosmetics and pharmaceuticals (creams, lotions, intravenous medications), chemical (paints, cleaning products), etc. LÄS MER

4. 13. Theoretical and numerical studies of sound propagation in low-Mach-number duct flows

   Författare :Chenyang Weng; Mats Åbom; Susann Boij; Ardeshir Hanifi; Anurag Agarwal; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aeroacoustics; Acoustic wave absorption; Acoustic wave propagation; Boundary layer turbulence; DNS; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : When sound waves propagate in a duct in the presence of turbulent flow, turbulent mixing can cause attenuation of the sound waves extra to that caused by the viscothermal effects. Experiments show that compared to the viscothermal effects, this turbulent absorption becomes the dominant contribution to the sound attenuation at sufficiently low frequencies. LÄS MER

5. 14. 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. 15. 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