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Aerodynamic

Name
George
Surname
Barakos
Scientific organization
University of Glasgow
Academic degree
PhD
Position
Professor
Scientific discipline
Machinery & Energy
Topic
Aerodynamic
Abstract
This paper presents the development and application of transport-based transition models for CFD. Two challenging problems are addressed including flow at low Mach and high Reynolds numbers as well as problems at high transonic Mach and moderate Reynolds numbers. The work suggests that with proper calibration this family of models can provide results with good engineering accuracy.
Keywords
CFD, Transition modelling
Summary

         In this paper, the potential of transition prediction methods is explored for modelling transitional shock-wave/boundary-layer interactions. The study is fuelled by the strong interest of researchers and airframe manufacturers in reducing drag of vehicles flying at transonic speeds. The principle of drag reduction via flow laminarity is valid, provided there is no need for the flow to sustain large pressure gradients or shocks. This is true since laminar boundary layers are less resistant to flow separation. It is therefore worthwhile to assess the performance of CFD methods in modelling laminar boundary layers that can be tripped to turbulent just before the interaction with a shock. At this work, the CFD solver of Liverpool University is used. The method is strongly implicit and for this reason the implementation of 4-equation, intermittency-based models requires special attention. The Navier-Stokes equations, the transport equations of the kinetic energy of turbulence and the turbulent frequency are inverted at the same time as the transport equations for the flow intermittency and the momentum thickness Reynolds number. The result is stable and robust convergence even for complex 3D flow cases. The method is demonstrated for the flow around the V2C section of the TFAST EU, F7 project. The results suggest that the intermittency based model captures the fundamental physics of the interaction but verification and validation is needed to ensure that accurate results can be obtained.