Sökning: "transonic flow"

Visar resultat 26 - 30 av 36 avhandlingar innehållade orden transonic flow.

1. 26. Advances in vortical flow prediction methods for design of delta-winged aircraft

   Författare :Simone Crippa; Arthur Rizzi; James Luckring; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; delta wing; slender wing; aircraft; vortex; VFE-2; CAWAPI; HISAC; Vehicle engineering; Farkostteknik;

   Sammanfattning : This thesis covers the field of vortex-flow dominated external aerodynamics. As part of the contribution to the AVT-113 task group it was possible to prove the feasibility of high Reynolds number CFD computations to resolve and thus better understand the peculiar dual vortex system encountered on the VFE-2 blunt leading edge delta wing at low to moderate incidences. LÄS MER

3. 27. Numerical Investigation of the Aerodynamic Vibration Excitation of High-Pressure Turbine Rotors

   Författare :Markus Jöcker; KTH; []
   Nyckelord :Aeroelasticity; Aerodynamics; Stator-Rotor Interaction; Excitation Mechanism; Unsteady Flow Computation; Forced Response; High Cycle Fatigue; Turbomachinery; Gas-Turbine; High-Pressure Turbine; Turbopump; CFD; Design;

   Sammanfattning : The design parameters axial gap and stator count of highpressure turbine stages are evaluated numerically towards theirinfluence on the unsteady aerodynamic excitation of rotorblades. Of particular interest is if and how unsteadyaerodynamic considerations in the design could reduce the riskofhigh cycle fatigue (HCF) failures of the turbine rotor. LÄS MER

4. 28. Simulations of compressible flows associatedwith internal combustion engines

   Författare :Olle Bodin; Laszlo Fuchs; Mihai Mihaescu; Michael Leschziner; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LES; Gas exhange; exhaust port; exhaust manifold; POD; DMD; exhaust; LES; Gasväxling; avgasport; avgasgrenrör; POD; DMD;

   Sammanfattning : Vehicles with internal combustion (IC) engines fueled by hydrocarbon compoundshave been used for more than 100 years for ground transportation.During these years and in particular the last decade, the environmental aspectsof IC engines have become a major political and research topic. LÄS MER

5. 29. Scaling techniques using CFD and wind tunnel measurements for use in aircraft design

   Författare :Karl Pettersson; Arthur Rizzi; Henrik Alfredsson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CFD; wind tunnel; scaling; Reynolds number effect; Vehicle engineering; Farkostteknik;

   Sammanfattning : This thesis deals with the problems of scaling aerodynamic data from wind tunnel conditions to free flight. The main challenges when this scaling should be performed is how the model support, wall interference and the potentially lower Reynolds number in the wind tunnel should be corrected. LÄS MER

7. 30. Methodologies for RANS-LES interfaces in turbulence-resolving simulations

   Författare :Sebastian Arvidson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; zonal RANS-LES; aeronautics; RANS-LES interfaces; Hybrid RANS-LES; grey-area mitigation; log-layer mismatch; embedded LES; LES length scale; LES;

   Sammanfattning : Hybrid Reynolds-Average Navier-Stokes (RANS)-Large-Eddy Simulations (LES) techniques are now seen by the aeronautical industry as the most promising turbulence-resolving approaches for complex high-Reynolds-number turbulent flows with regard to cost and accuracy. However, connecting RANS and LES simulated flows is a challenging task and needs special attention in order to increase simulation robustness and accuracy. LÄS MER