Séminaires à venir / Upcoming

    • The acoustics of flow over liners, par Ed Brambley, Université de Warwick, UK, invité par Gwénaël

      2017
      10
      16

      There are many examples of flow over non-rigid surfaces: flapping flags and acoustic liners in aircraft engines being two.  If liners absorb sound, do flags?  If flags flap, do liners?  In this talk, we will look at the acoustics and stability of flow over non-rigid surfaces, including experimental results (from LAUM), numerical results (from elsewhere), and theoretical results (from me); some of them may even agree!

    • Combining models and measurements by variational data assimilation, par Gilles Tissot, invité de Gwenael Gabard

      2017
      10
      31

      Abstract: 4D variational assimilation (4D-Var) is a generic methodology, widely used in weather forecast, that combines different sources of informations in order to estimate the state of a system, and eventually to calibrate predictive models. These informations can come from measurements, models and a priori knowledge of the system. Parameters of the model are modified in such a way that a given cost functional measuring the deviation of the solution to each source of information is minimised. This seminar will present two applications 4D-Var to fluid mechanics and aeroacoustics.

      I will first present an application of 4D-Var to render a reduced-order model based on dynamic mode decomposition (DMD) able to represent and predict the dynamics of a turbulent cylinder wake flow based on experimental particle image velocimetry (PIV) measurements.

      The second application is in the context of the aeroacoustics of turbulent jets. Linear hydrodynamic instability waves propagating within the turbulent jet flow are understood to be the main source of acoustic radiation at low angles (close to the jet axis). I will present how 4D-Var allows to identify the non-linearities responsible for the differences observed between measurements and linear stability models.

    • Les enjeux de la synthèse de champs sonores par Ambisonie d'ordre élevée, par Pierre Lecomte (post-doc à Celya), invité de Manuel

      2017
      11
      06







































    • (titre à venir) , par Angelo Farina, Prof. Université de Parme (Italie), invité par Pierrick

      2017
      11
      07

      (résumé à venir)

    • Measurement of nonlinear distortion of low-cost electret microphones, par Petr Honzik, invité de Antonin Novak

      2017
      11
      13

      The electret microphones are widely used in a large variety of applications such as consumer electronics or more recently in sensor networks for noise monitoring where the requirement of high number of sensor nodes raises the need of low-cost solutions. However, the nonlinear distortion originating in the microphone can significantly affect the accuracy of the noise level measurements. Since the measurement of the nonlinear distortion of microphones is affected by the nonlinear distortion of the speaker that emits the measuring signal, the method of identification of nolinear systems in series has to be applied. The experiences with measurements performed on low-cost electret microphones will be described and the main results will be presented.

    • (titre à venir), par Jiří Schimmel, invité de Bruno

      2017
      11
      28

      (résumé à venir)

    • pas de séminaire cette semaine, car soutenances LPAIV

      2018
      07
      10

      (pas de séminaire, car salle prise)