This thesis is focused on direct numerical simulation (DNS) of compressible and
incompressible fully developed and developing turbulent flows between isothermal
walls using a discontinuous Galerkin method (DGM).
Three cases (Ma = 0.2, 0.7 and 1.5) of DNS of turbulent channel flows between
isothermal walls with Re ~ 2800, based on bulk velocity and half channel width,
have been carried out. It is found that a power law seems to scale mean streamwise
velocity with Ma slightly better than the more usual log-law. Inner and outer scaling
of second-order and higher-order statistics have been analyzed. The linkage between
the pressure gradient and vorticity flux on the wall has been theoretically derived
and confirmed and they are highly correlated very close to the wall. The correlation
coefficients are influenced by Ma, and viscosity when Ma is high. The near-wall
spanwise streak spacing increases with Ma. Isosurfaces of the second invariant of the
velocity gradient tensor are more sparsely distributed and elongated as Ma increases.
DNS of turbulent isothermal-wall bounded flow subjected to favourable and adverse
pressure gradient (FPG, APG) at Ma ~ 0.2 and Reref ~ 428000, based on the
inlet bulk velocity and the streamwise length of the bottom wall, is also investigated.
The FPG/APG is obtained by imposing a concave/convex curvature on the top wall
of a plane channel. The flows on the bottom and top walls are tripped turbulent and laminar boundary layers, respectively. It is observed that the first and second order
statistics are strongly influenced by the pressure gradients. The cross-correlation
coefficients of the pressure gradients and vorticity flux remain constant across the
FPG/APG regions of the flat wall. High correlations between the streamwise/wallnormal
pressure gradient and the spanwise vorticity are found near the separation
region close to the curved top wall. The angle of inclined hairpin structure to streamwise
direction of the bottom wall is smaller (flatter) in the FPG region than the APG
region. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2009-12-21 13:59:53.084
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/5366 |
| Date | 22 December 2009 |
| Creators | Wei, Liang |
| Contributors | Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Format | 3555645 bytes, application/pdf |
| Rights | This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
| Relation | Canadian theses |
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