Compressibility, variable density and curvature effects on turbulent shear layers
Abstract/Contents
- Abstract
- Turbulent mixing layers occur between two streams of fluids with different kinematic and/or thermodynamic properties, and are fundamental flow features which influence the dynamics of a wide variety of applications, ranging from the mixing efficiency of fuel injection in internal combustion to vehicle loads in external aerodynamics. Two motivating applications behind this research include the study of high-speed jets in cross-flow and supersonic retro-propulsion, which occurs as aerospace vehicles use jet plumes to decelerate during entry, descent, and landing. Both these applications are highly influenced by hot jet plumes under highly compressible conditions which exhibit significant streamwise curvature. Simulating the entire flow field associated with such applications is extremely computationally expensive; capturing all important flow features at full resolution is exorbitant for the purposes of engineering design. Thus, grasping the full behavior of turbulent mixing layers in a representative parameter space enables the development of models which can reliably and accurately predict the complex flow fields present in these engineering applications. This work enriches the present understanding of mixing in turbulent shear layers via the systematic inclusion of compressibility, variable density, and streamwise curvature effects. The spreading, or growth rate, of turbulent shear layers is known to decrease with increasing compressibility. Dilatational velocities and pressure-dilatation magnitudes show little contribution to shear layer growth rates, even under highly compressible conditions. A new turbulent length and velocity scale is introduced and shown to scale key turbulent quantities. Inclusion of freestream density variations are also known to decreasing mixing layer growth rates. Trends with increasing compressibility and the importance of mixing layer asymmetry are identified--shear layer centerlines and turbulent stresses in variable density shear layers are biased towards the less-dense freestream, which reduces the turbulent mixing of the mean momentum profile and corresponding growth rates. The combined effects of compressibility and streamwise curvature are demonstrated to be comparable for the selected parameter space. Shear layer growth rates are dominated by the freestream density ratio when streamwise curvature is significant. Changes to model predictions of turbulent growth rates and turbulent kinetic energy levels resulting from various model modifications are evaluated. Reduced accuracy in model predictions of turbulent kinetic energy magnitudes under curved conditions, even with the inclusion of compressibility and curvature modifications, is demonstrated.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2022; ©2022 |
| Publication date | 2022; 2022 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Matsuno, Kristen |
|---|---|
| Degree supervisor | Lele, Sanjiva K. (Sanjiva Keshava), 1958- |
| Thesis advisor | Lele, Sanjiva K. (Sanjiva Keshava), 1958- |
| Thesis advisor | Alonso, Juan José, 1968- |
| Thesis advisor | Mani, Ali, (Professor of mechanical engineering) |
| Thesis advisor | Moin, Parviz |
| Degree committee member | Alonso, Juan José, 1968- |
| Degree committee member | Mani, Ali, (Professor of mechanical engineering) |
| Degree committee member | Moin, Parviz |
| Associated with | Stanford University, Department of Mechanical Engineering |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Kristen V. Matsuno. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2022. |
| Location | https://purl.stanford.edu/zy339hc0667 |
Access conditions
- Copyright
- © 2022 by Kristen Matsuno
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