The objective of the thesis is to characterize the linear and nonlinear aspects of inertial
and pressure effects in turbulent flows. In the first part of the study, computations of
Navier-Stokes and 3D Burgers equations are performed in the rapid distortion (RD) limit
to analyze the inviscid linear processes in homogeneous turbulence. By contrasting the
results of Navier- Stokes RD equations and Burgers RD equations, the effect of pressure
can be isolated. The evolution of turbulent kinetic energy and anisotropy components
and invariants are examined. In the second part of the thesis, the velocity gradient
dynamics in turbulent flows are studied with the help of inviscid 3D Burgers equations
and restricted Euler equations. The analytical asymptotic solutions of velocity gradient
tensor are obtained for both Burgers and restricted Euler equations. Numerical
computations are also performed to identify the stable solutions. The results are
compared and contrasted to identify the effect of pressure on nonlinear velocity gradient
dynamics. Of particular interest are the sign of the intermediate principle strain-rate and
tendency of vorticity to align with the intermediate principle strain-rate. These aspects of
velocity gradients provide valuable insight into the role of pressure in the energy cascade
process.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/2506 |
| Date | 01 November 2005 |
| Creators | Bikkani, Ravi Kiran |
| Contributors | Girimaji, Sharath S. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | 414031 bytes, electronic, application/pdf, born digital |
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