Engineering Turbulence – Part II: Lifting The Wright Way!

"It's easy to explain how a rocket works, but explaining how a wing works takes a rocket scientist..." - Philippe Spalart (senior technical fellow - the Boeing company) The intention of this set of posts is to embark on a journey of connecting the dots between CFD and turbulence modeling with the phenomenological and practical …

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Engineering Turbulence – Part I: Phenomenology

"If you want to be a Millionaire, start with a billion dollars and launch a new airline ..." - Richard Branson The intention of this set of posts is to embark on a journey of connecting the dots between CFD and turbulence modeling with the phenomenological and practical concepts of engineering aerodynamics. Even though it …

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Turbulence Modeling – Near Wall Treatment

Most of nowadays CFD simulations are conducted with the Reynolds Averaging approach. Reynolds Averaged Navier-Stokes (RANS) simulation, the "working horse" of industrial CFD is based on the Reynolds decomposition according to which a flow variable is decomposed into mean and fluctuating quantities. When the decomposition is applied to Navier-Stokes equation an extra term known as the Reynolds …

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GEKO – And Then There Were Six… – PART I

"with four parameters I can fit an elephant, with five I can make him wiggle his trunk..." - John von Neumann Most of nowadays CFD simulations of engineering applications are conducted via the Reynolds Averaging approach. Reynolds-Averaged Navier-Stokes (RANS) simulation is based on the Reynolds decomposition according to which a flow variable is decomposed into …

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Turbulence Modeling – The Gist

The attached presentation is a concise description of turbulence modeling approaches, based on the portion of Turbulence Modeling of past CFD courses I have had the opportunity to lead. It has many links to more elaborated blog posts relating to specific turbulence models and its foundations. Update 29/3/18: Stress-Blended Eddy Simulation (SBES) (slides 86-87) Update …

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Know Thy Mesh – Mesh Quality – Part I

Many would argue that your CFD solution is as good as the mesh behind it. Many aspects of the mesh have a vital contribution to simulation accuracy, and include among others the type of physics models simulated, the details of the solution to the particular simulation, chosen discretization scheme and geometric mesh properties having to …

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Numerical Schemes in CFD: Upwinding and The Cell-Reynolds Problem

There are three broad methods employed for discretizing the governing partial differential equations of a fluid flow: Finite Difference Methods (FDM) Finite Element Methods (FEM) Finite Volume Methods (FVM) Finite element and finite volume methods (FEM and FVM) are both based on dividing the flow domain into small cells, or volumes. These may possibly take any shape …

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