Sökning: "drag reduction"

Visar resultat 31 - 35 av 57 avhandlingar innehållade orden drag reduction.

1. 31. Simulation Studies for Improved Efficiency in Road and Rail Freight Transports

   Författare :Ingrid Johansson; Markus Bohlin; Oskar Fröidh; Behzad Kordnejad; Carl-William Palmqvist; C. Tyler Dick; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; heavy-duty vehicle platooning; road traffic simulation; intelligent transport systems; optimal control; longitudinal cruise control; fuel economy; railway traffic simulation; microscopic simulation; macroscopic simulation; freight trains; early departures; capacity; railway stations; strategic planning; timetable compression; UIC Code 406; Transportsystem; Transport Systems;

   Sammanfattning : The demand for road and rail freight transport continues to grow with the expanding economy, while the climate crisis requires reduction in greenhouse gas emissions. Therefore, tools and solutions for reducing fossil fuel use and enabling more efficient use of infrastructure are needed. LÄS MER

3. 32. Study of adverse-pressure-gradient effects on a flat-plate boundary layer at high Reynolds numbers

   Författare :Ramón Pozuelo; Ricardo Vinuesa; Philipp Schlatter; Ivette Rodriguez; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulence; simulations; turbulent boundary layers; adverse pressure gradients.; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : Turbulent boundary layers are present in many aspects of life, from the weather and wind currents to transportation, production of energy or mixing processes. Understanding turbulent motions can allow for an improvement and development of technical devices, techniques or diagnosis of phenomena where a fluid flow is in the turbulent regime. LÄS MER

4. 33. On an Efficient Method fo Time-Domain Computational Aeroelasticity

   Författare :David Eller; Ulf Ringertz; Paolo Mantegazza; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aeroelasticity; unsteady aerodynamics; boundary element method; multidisciplinary simulation; Vehicle engineering; Farkostteknik;

   Sammanfattning : The present thesis summarizes work on developing a method for unsteady aerodynamic analysis primarily for aeroelastic simulations. In contrast to widely used prediction tools based on frequency-domain representations, the current approach aims to provide a time-domain simulation capability which can be readily integrated with possibly nonlinear structural and control system models. LÄS MER

5. 34. Creep modeling and first-principles investigation of high-temperature alloys

   Författare :Jing Zhang; Pavel A. Korzhavyi; Rolf Sandström; Gunther Eggeler; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Austenitic stainless steels; Nickel-based superalloys; Fundamental creep models; EMTO-CPA method; Quasi-harmonic Debye model; Thermo-mechanical properties; High temperatures.; Teknisk materialvetenskap; Materials Science and Engineering;

   Sammanfattning : Stainless steels and nickel-based superalloys are materials that have been widely used to manufacture components servicing at high temperatures. Creep strength is one of the most important properties in such conditions. LÄS MER

7. 35. Turbulent flows over permissive boundaries and porous walls

   Författare :Seyed Morteza Habibi Khorasani; Shervin Bagheri; Geert Brethouwer; Alfredo Soldati; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct numerical simulations; wall-bounded turbulence; flow control; porous walls; heat transfer; Direkta numeriska simuleringar; väggbunden turbulens; flödeskontroll; porösa väggar; värmeöverföring; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : This thesis investigates how in wall-bounded turbulent flows changes to the wall can induce changes in the flow. To this end, we investigate the use of wall boundary conditions meant to mimic the effect of textured surfaces. LÄS MER