Prediction of Transitional Boundary Layers and Fully Turbulent Free Shear Flows, Using Reynolds Averaged Navier-Stokes Models
Title | Prediction of Transitional Boundary Layers and Fully Turbulent Free Shear Flows, Using Reynolds Averaged Navier-Stokes Models PDF eBook |
Author | Maurin Lopez |
Publisher | |
Pages | 105 |
Release | 2014 |
Genre | |
ISBN |
One of the biggest unsolved problems of modern physics is the turbulence phenomena in fluid flow. The appearance of turbulence in a flow system is regularly determined by velocity and length scales of the system. If those scales are small the motion of the fluid is laminar, but at larger scales, disturbances appear and grow, leading the flow field to transition to a fully turbulent state. The prediction of transitional flow is critical for many complex fluid flow applications, such as aeronautical, aerospace, biomedical, automotive, chemical processing, heating and cooling systems, and meteorology. For example, in some cases the flow may remain laminar throughout a significant portion of a given domain, and fully turbulent simulations may produce results that can lead to inaccurate conclusions or inefficient design, due to an inability to resolve the details of the transition process. This work aims to develop, implement, and test a new model concept for the prediction of transitional flows using a linear eddy-viscosity RANS approach. The effects of transition are included through one additional transport equation for u2 as an alternative to the Laminar Kinetic Energy (LKE) framework. Here u2 is interpreted as the energy of fully turbulent, three-dimensional velocity fluctuations. This dissertation presents two new single-point, physics-based turbulence models based on the transitional methodology mentioned above. The first one uses an existing transitional model as a baseline which is modified to accurately capture the physics of fully turbulent free shear flows. The model formulation was tested over several boundary layer and free shear flow test cases. The simulations show accurate results, qualitatively equal to the baseline model on transitional boundary layer test cases, and substantially improved over the baseline model for free shear flows. The second model uses the SST k-w fully turbulent model and again the effects of transition are included through one additional transport equation for u2. An initial version of the model is presented here. Simplicity of the formulation and ease of extension to other baseline models are two potential advantages of the new method.
Scientific and Technical Aerospace Reports
Title | Scientific and Technical Aerospace Reports PDF eBook |
Author | |
Publisher | |
Pages | 426 |
Release | 1995 |
Genre | Aeronautics |
ISBN |
Numerical Simulation of Unsteady Flows and Transition to Turbulence
Title | Numerical Simulation of Unsteady Flows and Transition to Turbulence PDF eBook |
Author | O. Pironneau |
Publisher | Cambridge University Press |
Pages | 536 |
Release | 1992-07-31 |
Genre | Mathematics |
ISBN | 9780521416184 |
The workshop concentrated on the following turbulence test cases: T1 Boundary layer in an S-shaped duct; T2 Periodic array of cylinders in a channel; T3 Transition in a boundary layer under the influence of free-stream turbulence; T4 & T5: Axisymmetric confined jet flows.
Boundary Layer Flows
Title | Boundary Layer Flows PDF eBook |
Author | Vallampati Ramachandra Prasad |
Publisher | BoD – Books on Demand |
Pages | 236 |
Release | 2020-01-22 |
Genre | Mathematics |
ISBN | 1839681853 |
Written by experts in the field, this book, "Boundary Layer Flows - Theory, Applications, and Numerical Methods" provides readers with the opportunity to explore its theoretical and experimental studies and their importance to the nonlinear theory of boundary layer flows, the theory of heat and mass transfer, and the dynamics of fluid. With the theory's importance for a wide variety of applications, applied mathematicians, scientists, and engineers - especially those in fluid dynamics - along with engineers of aeronautics, will undoubtedly welcome this authoritative, up-to-date book.
Applied Mechanics Reviews
Title | Applied Mechanics Reviews PDF eBook |
Author | |
Publisher | |
Pages | 592 |
Release | 1974 |
Genre | Mechanics, Applied |
ISBN |
NASA Technical Paper
Title | NASA Technical Paper PDF eBook |
Author | |
Publisher | |
Pages | 52 |
Release | 1990 |
Genre | Science |
ISBN |
NASA Technical Paper
Title | NASA Technical Paper PDF eBook |
Author | United States. National Aeronautics and Space Administration |
Publisher | |
Pages | 380 |
Release | 1990 |
Genre | Aeronautics |
ISBN |