Sökning: "Direct Numerical Simulation DNS"

Visar resultat 11 - 15 av 38 avhandlingar innehållade orden Direct Numerical Simulation DNS.

1. 11. Numerical studies of turbulent flames in wall-jet flows

   Författare :Zeinab Pouransari; Arne V. Johansson; Yves D'Angelo; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulence; combustion; direct numerical simulation; wall-jet; heat release effects; mixing scales; non-premixed flame; wall heat transfer; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : The present thesis deals with the fundamental aspects of turbulent mixing and non-premixed combustion in the wall-jet flow, which has a close resemblance to many industrial applications. Direct numerical simulations (DNS) of turbulent wall-jets with isothermal and exothermic reactions are performed. LÄS MER

3. 12. Numerical modelling of particulate matter deposition in exhaust gas after-treatment systems

   Författare :Ananda Subramani Kannan; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Immersed boundary method; DNS; Brownian motion; PM transformation and Rarefied gas; Nanoscales;

   Sammanfattning : As urban air quality declines, the corresponding levels of particulate matter (PM), that include pollutants such as sulfates, nitrates and black carbon, rise posing the greatest risks to human health. Hence, the control of these particulate emissions constitutes a major global challenge that commands serious attention. LÄS MER

4. 13. Direct Numerical Simulation of Boundary-layer Transition with Free-stream Turbulence

   Författare :Kristina Durovic; Dan Henningson; Ardeshir Hanifi; Philipp Schlatter; Tamer Zaki; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : This thesis considers the generation and influence of free-stream turbulence toboundary layer transition on both flat and curved bodies in the flow. Variousflow configurations such as flow around the flat plate with a sharp leading edgeand low-pressure turbine blades are considered. LÄS MER

5. 14. CFD Study of Molten Pool Convection in a Reactor Vessel during a Severe Accident

   Författare :Boshen Bian; Walter Villanueva; Sevostian Bechta; Weimin Ma; Shuisheng He; KTH; []
   Nyckelord :Severe accident; Corium; Natural convection; Turbulence; Scalability; Direct numerical simulation DNS .; Svåra haverier; härdsmälta; naturlig konvektion; turbulens; skalbarhet; direkt numerisk simulering DNS .; Physics; Fysik;

   Sammanfattning : During severe accidents in nuclear reactors, the core and internal structures can melt down and relocate into the reactor pressure vessel (RPV) lower head (LH) forming there a stratified molten corium pool. The pool generally consists of superheated oxidic and metallic liquid layers imposing thermo-mechanical loads on the RPV wall. LÄS MER

7. 15. Spectral-element simulations of turbulent wall-bounded flows including transition and separation

   Författare :Johan Malm; Dan Henningson; Philipp Schlatter; Suad Jakirlic; KTH; []
   Nyckelord :spectral-element method; direct numerical simulation DNS ; large-eddy simulation LES ; turbulence; transition; over-integration; three-dimensional separation; massively parallel simulations; proper orthogonal decomposition POD ; Koopman modes; vorticity stretching; coherence; SRA - E-vetenskap SeRC ; SRA - E-Science SeRC ;

   Sammanfattning : The spectral-element method (SEM) is used to study wall-bounded turbulent flowsin moderately complex geometries. The first part of the thesis is devoted to simulations of canonical flow cases, such as temporal K-type transitionand turbulent channel flow, to investigate general resolution requirements and computational efficiency of the numerical code nek5000. LÄS MER