Reconstruction of time-averaged and unsteady data in open-flows using non-linear optimization techniques and hydrodynamic stability

Duration: 46 mins 35 secs

Description:	Presentation by Denis Sipp (Onera, France) at online meeting on 'Data Assimilation in Fluid Mechanics', organised by the UK Fluids Network Special Interest Group 'Flow instability, modelling and control', 27th May 2020.


Created:	2020-06-16 10:16
Collection:	Data Assimilation in Fluid Mechanics - 1st online meeting of UKFN SIG 'Flow instability, modelling and control'
Publisher:	University of Cambridge
Copyright:	Denis Sipp
Language:	eng (English)


Abstract:	The accurate reconstruction of time-averaged and unsteady data in wind-tunnels from few measurements has become an important topic in the aerospace industry. We will show here how the use of time-averaged (Reynolds-Averaged Navier-Stokes) and fully unsteady (Navier-Stokes) models may help reconstruct a whole flow field from scarce measurements using non-linear optimization techniques. This will be illustrated on experimental and numerical configurations exhibiting separation, such as bluff-bodies, backward facing step flows or jet flows. Finally, we will show how the knowledge of the time-averaged flow and its hydrodynamic stability properties may provide an alternative efficient way of reconstructing large-scale and low-frequency unsteady features in turbulent flows.

Abstract:

The accurate reconstruction of time-averaged and unsteady data in wind-tunnels from few measurements has become an important topic in the aerospace industry. We will show here how the use of time-averaged (Reynolds-Averaged Navier-Stokes) and fully unsteady (Navier-Stokes) models may help reconstruct a whole flow field from scarce measurements using non-linear optimization techniques. This will be illustrated on experimental and numerical configurations exhibiting separation, such as bluff-bodies, backward facing step flows or jet flows. Finally, we will show how the knowledge of the time-averaged flow and its hydrodynamic stability properties may provide an alternative efficient way of reconstructing large-scale and low-frequency unsteady features in turbulent flows.

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