Search for dissertations about: "DNS"

Showing result 6 - 10 of 102 swedish dissertations containing the word DNS.

2. 6. Numerical frameworks for small-scale bubble dynamics

   Author : Niklas Hidman; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; multiphase; phase change; DNS; moving reference frame; Bubbly flows; cavitation; laser-induced;

   Abstract : Designing efficient bubbly flow systems requires the prediction of the dynamics of the bubbles, the liquid and how the gas and liquid phases interact. Currently, the complex dynamics in bubbly flows are not yet fully explained, and we rely on incomplete models in our numerical methods. READ MORE

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

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

   Abstract : 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. READ MORE

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

   Author : Nicolò Fabbiane; Dan S. Henningson; Shervin Bagheri; Denis Sipp; KTH; []
   Keywords : 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;

   Abstract : 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. READ MORE

6. 9. Transport Barriers in Plasmas and Fluids

   Author : Robert Moestam; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; DNS; transport barriers; Zonal flows; L-H mode transition; turbulence simulations; drift waves; flux tube simulations; nonlinear instabilities; linear instabilities;

   Abstract : In the present work different mechanisms for generation and suppression of turbulence are studied. The suppression of nonlinearly generated turbulence stabilized by temperature boundary conditions as well as turbulence generated by linear instabilities and suppressed by nonlinearly generated secondary flows are treated. READ MORE

7. 10. Numerical modelling of particulate matter deposition in exhaust gas after-treatment systems

   Author : Ananda Subramani Kannan; Chalmers tekniska högskola; []
   Keywords : 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;

   Abstract : 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. READ MORE