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Bounded energy states in homogeneous turbulent shear flow: an alternative view
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Bernard, Peter S. Speziale, Charles G. |
| Copyright Year | 1990 |
| Description | The equilibrium structure of homogeneous turbulent shear flow is investigated from a theoretical standpoint. Existing turbulence models, in apparent agreement with physical and numerical experiments, predict an unbounded exponential time growth of the turbulent kinetic energy and dissipation rate; only the anisotropy tensor and turbulent time scale reach a structural equilibrium. It is shown that if vortex stretching is accounted for in the dissipation rate transport equation, then there can exist equilibrium solutions, with bounded energy states, where the turbulence production is balanced by its dissipation. Illustrative calculations are present for a k-epsilon model modified to account for vortex stretching. The calculations indicate an initial exponential time growth of the turbulent kinetic energy and dissipation rate for elapsed times that are as large as those considered in any of the previously conducted physical or numerical experiments on homogeneous shear flow. However, vortex stretching eventually takes over and forces a production-equals-dissipation equilibrium with bounded energy states. The validity of this result is further supported by an independent theoretical argument. It is concluded that the generally accepted structural equilibrium for homogeneous shear flow with unbounded component energies is in need of re-examination. |
| File Size | 1084093 |
| Page Count | 38 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19910000924 |
| Archival Resource Key | ark:/13960/t87h6h254 |
| Language | English |
| Publisher Date | 1990-10-01 |
| Access Restriction | Open |
| Subject Keyword | Fluid Mechanics And Heat Transfer Tensors Turbulent Flow Energy Dissipation Anisotropy Vortices Shear Flow K-epsilon Turbulence Model Mathematical Models Kinetic Energy Equilibrium Stretching Homogeneous Turbulence Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
