First aerodynamic-aero-acoustic chaining created with an exchange surface crossed by a turbulentflow ("LES" CFD- "Euler" CAA)... This first aerodynamic-aero-acoustic chaining, created with an exchange surface crossed by a turbulentflow, opens the way to future complete aero-acoustic computations for configurations that are today impossible using non- coupled CFD(* Computational Fluid Dynamics) and CAA:* see below
This noise is a result of multiple interactions between the turbulentflows and the various elements that make up the cell... Appearance of the turbulentflow on a background of non- structured mesh[ Cedre Calculation... Technique for the solving of turbulentflow equations in which the large scales of movement are solved explicitly while the small scales (smaller that the calculation meshes) are modeled by" a vortical viscosity" term
Detail of a model of turbulentflow in the vicinity of an aircraft bay... "We are assuming that the angle of stall depends on the transition between a laminar (regular) flow and a turbulentflow (one that generates vortices) ",adds Ivan Mary... Downstream from the transition, the turbulentflow is calculated using statistical methods
This is also true of turbulentflows where the large-scale vortex structures move constantly and in an unpredictable fashion". Hence the need to develop" unsteady" physical models and numerical methods that can be used to calculate the results of these models
For investigations of flow fields with pronounced spatial structures and/or rapid temporal or spatial changes (transition from laminar to turbulentflow, coherent structures, pitching airfoils in transonic flows with shocks, rotors, test facilities with short run time, etc.) new experimental techniques, such as PIV are required which allow to capture the flow velocity of large flow fields instantaneously
It allows separations, vortices and turbulent areas to be revealed, in order to understand the structure of the flow and also to prepare further measurements with a hot wire anemometer, or a laser velocimeter for example. Laser tomoscopy is a visualization method for high-speed flows, up to supersonic speeds
An acenaphthene film spread over the wing has the property of being" ripped off" (we say that it is sublimated) when the flow is turbulent, which helps to differentiate the laminar areas (white) from the turbulent areas (black), with the boundary characterizing the transition... It is an essential parameter for characterizing the flow rate in the boundary layer close to the wall: fully laminar at very low Re, fully turbulent for very large Re, etc.)
