Sökning: "adverse-pressure-gradient turbulent boundary layer"

Visar resultat 6 - 10 av 10 avhandlingar innehållade orden adverse-pressure-gradient turbulent boundary layer.

1. 6. Experimental studies of turbulent boundary layer separation and control

   Författare :Kristian Angele; KTH; []
   Nyckelord :turbulence; boundary layer; separition; adverse pressure graddient;

   Sammanfattning : The object ofthe present work is to experimentally study thecase ofa turbulent boundary layer subjected to an AdversePressure Gradient (APG) with separation and reattachment. Thisconstitutes a good test case for advanced turbulence modeling. LÄS MER

3. 7. Computational fluid-dynamics investigations of vortex generators for flow-separation control

   Författare :Florian von Stillfried; Arne Johansson; Stefan Wallin; Jonathan Morrison; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow-separation control; vane vortex generator; vortex generator jet; zero-pressure-gradient turbulent boundary layer; adverse-pressure-gradient turbulent boundary layer; statistical modelling; turbulence; Reynolds stress- transport model; computational fluid dynamics;

   Sammanfattning : Many flow cases in fluid dynamics face undesirable flow separation due to ad-verse pressure gradients on wall boundaries. This occurs, for example, due togeometrical reasons as in a highly curved turbine-inlet duct or on flow-controlsurfaces such as wing trailing-edge flaps within a certain angle-of-attack range. LÄS MER

4. 8. Simulations of turbulent boundary layers with suction and pressure gradients

   Författare :Alexandra Bobke; Philipp Schlatter; Ramis Örlü; Ayse Gul Gungor; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layers; near-wall turbulence; history effects; asymptotic suction boundary layers; large-eddy simulation;

   Sammanfattning : The focus of the present licentiate thesis is on the effect of suction and pressure gradients on turbulent boundary-layer flows, which are investigated separately through performing numerical simulations.The first part aims at assessing history and development effects on adverse pressure-gradient (APG) turbulent boundary layers (TBL). LÄS MER

5. 9. Stability and transition on wind turbine blades

   Författare :Thales Coelho Leite Fava; Ardeshir Hanifi; Dan Henningson; Stefania Cherubini; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Boundary layer stability; free-stream turbulence; laminar-turbulent transition; low-frequency oscillations; rotation effects; wind turbine blades.; Gränsskiktsstabilitet; friströmsturbulens; laminär-turbulent omslag; lågfrekventa svängningar; rotationseffekter; vindkraftverksblad.; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : Transition on wind turbine blades is a highly complex phenomenon due to the myriad effects influencing the process. This thesis studies some of them, namely free-stream turbulence (FST), rotation, and three-dimensionality. The investigations employ large eddy simulations (LES) with and without (implicit or wall-resolved LES) a subgrid-scale model. LÄS MER

7. 10. Simulation methods for hydropower flows : modeling and validation experiments

   Författare :T. Fredrik Engström; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strömningslära; Fluid Mechanics;

   Sammanfattning : My research project aims for more accurate modeling of the flow in hydropower plants. By accurate modeling, it is possible to try different modifications on existing plants in an affordable manner. Also, entirely new designs can be tested before realization. Hydropower delivers almost 50% of Sweden's electricity demand with a production of 74 TWh. LÄS MER