Sökning: "drag reduction"

Visar resultat 6 - 10 av 57 avhandlingar innehållade orden drag reduction.

1. 6. Active Flow Control for Aircrafts and Heavy Vehicles

   Författare :Mohammad El-Alti; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Trucks; Drag reduction; Bluff-body; Large-eddy Simulation; Wake; Tilt-rotor wing; optimization; Aircrafts; Heavy vehicles; Active and Passive Flow Control; Response surface methodology; Synthetic-jet Actuator;

   Sammanfattning : Bluff-body flows are dominated by large dissipative vortex-shedding wakes with low mean pressure compared to the high pressure on their frontal area. This induced pressure difference is the major contribution to the total aerodynamic drag. LÄS MER

3. 7. Modelling and control of turbulent and transitional flows

   Författare :Pierluigi Morra; Dan S. Henningson; Ardeshir Hanifi; André V. G. Cavalieri; Shervin Bagheri; Aimee S. Morgans; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; reduced order modeling; flow control; resolvent analysis; transi- tional boundary layer; turbulent boundary layer; drag reduction; high-fidelity wall-turbulence modelling; modellreduktion; strömningskontroll; resolvent analys; laminär- turbulent omslag; turbulent gränsskikt; motståndsminskning; väggturbulens modellering; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : The dynamics of fluid motion can accurately be described by the Navier– Stokes equations. Manipulating these equations to reduce their complexity but preserving their main characteristics has always been a key research activity in the field of fluid mechanics. LÄS MER

4. 8. Aerodynamics of vehicle platooning

   Författare :Johannes Törnell; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; close proximity; drag; platooning; cab over engine; aerodynamics; yaw; wake; side wind; truck; inter-vehicle distance; lateral offset;

   Sammanfattning : Many factors are pushing automotive manufacturers to increase the efficiency of their fleets; some of these are legislative (requiring reduced greenhouse gas emissions) as well as ensuring sufficient range and power consumption in electric vehicles. An important part of improving the energy efficiency of road vehicles is reducing their aerodynamic drag. LÄS MER

5. 9. Metabolic regulation of nitrogen fixation in Rhodospirillum rubrum

   Författare :He Wang; Stefan Nordlund; Patrick Hallenbeck; Stockholms universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Rhodospirillum rubrum; nitrogen fixation; switch-off; PII; AmtB1; DRAG; Biochemistry; Biokemi; Biochemistry; biokemi;

   Sammanfattning : Nitrogen, along with carbon, hydrogen and oxygen, is amongst the most abundant elements in all living cells. The capability to convert atmospheric dinitrogen to biologically usable nitrogen compounds is only found in some prokaryotes. LÄS MER

7. 10. Aerodynamic Investigation of Truck-Trailer Combinations

   Författare :Helena Martini; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aerodynamics; vehicle combinations; trucks; drag reduction;

   Sammanfattning : In today’s society, increasing fuel prices and the constantly evolving emission legislation, forces the vehicle industry to develop new techniques for the propul- sion of vehicles, and optimization of existing technology. Trucks constitute a significant proportion of the transportation system, consequently it is of great importance to ensure as low an impact as possible on the environment. LÄS MER