Computational Fluid Dynamics (CFD) has been widely used in scientific research and engineering designs of aerospace vehicles. However, most Reynolds-averaged Navier-Stokes CFD applications today still assume fully turbulent flows, and so are unable to capture the boundary layer transition phenomenon. In the present study, the Local Correlation-based Transition Model (LCTM) was investigated and implemented in an unstructured CFD solver - U2NCLE, which is coupled with both one-equation Spalart-Allmaras (S-A) and two-equations Shear Stress Transport (SST) turbulence models. An innovative method was developed to evaluate the local free stream turbulence intensity for the transition model coupled with the S-A turbulence model. The current transition model was systematically validated on several benchmark cases including a flat plate with and without pressure gradients, two-dimensional airfoils, and realistic three-dimensional helicopter rotors. Both the S-A and SST based transition models were also used to predict the aerodynamic interactions in a lift fan configuration, to further explore the unsteady aerodynamic phenomena for internal viscous flows.

Turbulence is one of the key issues in tackling engineering flow problems. As powerful computers and accurate numerical methods are now available for solving the flow equations, and since engineering applications nearly always involve turbulence effects, the reliability of CFD analysis depends increasingly on the performance of the turbulence models. This series of symposia provides a forum for presenting and discussing new developments in the area of turbulence modelling and measurements, with particular emphasis on engineering-related problems. The papers in this set of proceedings were presented at the 5th International Symposium on Engineering Turbulence Modelling and Measurements in September 2002. They look at a variety of areas, including: Turbulence modelling; Direct and large-eddy simulations; Applications of turbulence models; Experimental studies; Transition; Turbulence control; Aerodynamic flow; Aero-acoustics; Turbomachinery flows; Heat transfer; Combustion systems; Two-phase flows. These papers are preceded by a section containing 6 invited papers covering various aspects of turbulence modelling and simulation as well as their practical application, combustion modelling and particle-image velocimetry.

Proceedings of the world renowned ERCOFTAC (International Symposium on Engineering Turbulence Modelling and Measurements).The proceedings include papers dealing with the following areas of turbulence:·Eddy-viscosity and second-order RANS models ·Direct and large-eddy simulations and deductions for conventional modelling ·Measurement and visualization techniques, experimental studies ·Turbulence control ·Transition and effects of curvature, rotation and buoyancy on turbulence ·Aero-acoustics ·Heat and mass transfer and chemically reacting flows ·Compressible flows, shock phenomena ·Two-phase flows ·Applications in aerospace engineering, turbomachinery and reciprocating engines, industrial aerodynamics and wind engineering, and selected chemical engineering problems Turbulence remains one of the key issues in tackling engineering flow problems. These problems are solved more and more by CFD analysis, the reliability of which depends strongly on the performance of the turbulence models employed. Successful simulation of turbulence requires the understanding of the complex physical phenomena involved and suitable models for describing the turbulent momentum, heat and mass transfer. For the understanding of turbulence phenomena, experiments are indispensable, but they are equally important for providing data for the development and testing of turbulence models and hence for CFD software validation. As in other fields of Science, in the rapidly developing discipline of turbulence, swift progress can be achieved only by keeping up to date with recent advances all over the world and by exchanging ideas with colleagues active in related fields.

A new laminar-turbulent transition model for low-turbulence external aerodynamic applications is presented that incorporates linear stability theory in a manner compatible with modern computational fluid dynamics solvers. The model uses a new transport equation that describes the growth of the maximum Tollmien-Schlichting instability amplitude in the presence of a boundary layer. To avoid the need for integration paths and non-local operations, a locally defined non-dimensional pressure-gradient parameter is used that serves as an estimator of the integral boundary-layer properties. The model has been implemented into the OVERFLOW 2.2f solver and interacts with the Spalart-Allmaras and Menter SST eddy-viscosity turbulence models. Comparisons of predictions using the new transition model with high-quality wind-tunnel measurements of airfoil section characteristics validate the predictive qualities of the model. Predictions for three-dimensional aircraft and wing geometries show the correct qualitative behavior even though limited experimental data are available. These cases also demonstrate that the model is well-behaved about general aeronautical configurations. These cases confirm that the new transition model is an improvement over the current state of the art in computational fluid dynamics transition modeling by providing more accurate solutions at approximately half the added computational expense.

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.

This book gives a mathematical insight--including intermediate derivation steps--into engineering physics and turbulence modeling related to an anisotropic modification to the Boussinesq hypothesis (deformation theory) coupled with the similarity theory of velocity fluctuations. Through mathematical derivations and their explanations, the reader will be able to understand new theoretical concepts quickly, including how to put a new hypothesis on the anisotropic Reynolds stress tensor into engineering practice. The anisotropic modification to the eddy viscosity hypothesis is in the center of research interest, however, the unification of the deformation theory and the anisotropic similarity theory of turbulent velocity fluctuations is still missing from the literature. This book brings a mathematically challenging subject closer to graduate students and researchers who are developing the next generation of anisotropic turbulence models. Indispensable for graduate students, researchers and scientists in fluid mechanics and mechanical engineering.

This book reports the latest development and trends in the low Re number aerodynamics, transition from laminar to turbulence, unsteady low Reynolds number flows, experimental studies, numerical transition modelling, control of low Re number flows, and MAV wing aerodynamics. The contributors to each chapter are fluid mechanics and aerodynamics scientists and engineers with strong expertise in their respective fields. As a whole, the studies presented here reveal important new directions toward the realization of applications of MAV and wind turbine blades.