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Presentation of ENSTA ParisTech activities in the BATWOMAN ITN. 1st BATWOMAN workshop August 25-27 2014. Teams involved in the network. Fluid Dynamics and Acoustics (DFA) of the Department of Mechanical Engineering (UME)
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Presentation of ENSTA ParisTech activities in the BATWOMAN ITN 1st BATWOMAN workshop August 25-27 2014
Teams involved in the network • Fluid Dynamics and Acoustics (DFA) of the Department of Mechanical Engineering (UME) • Wave Propagation: Mathematical Study and Simulation (POEMS) of the Applied Mathematics Department (UMA) 1st BATWOMAN workshop August 25-27 2014
Research themes at DFA • Fundamental research and industrial applications • Transportation aerodynamics • Turbulence phenomena • Wind turbine noise • Loudspeakers, transportation noise • Musical Acoustics • Nonlinear modes • Flow-induced vibrations associated to nuclear energy production • Energy harvesting Vibrations Aeroelasticity Structural Acoustics Fluid-Structure Interaction Fluid dynamics Aeroacoustics Acoustics 1st BATWOMAN workshop August 25-27 2014
Research themes at POEMS 1st BATWOMAN workshop August 25-27 2014
Structural Acoustics • Damping in thin plates : • Time-domain model of a reverberation plate, thermoelastic damping • Time-domain damping models using digital filters • Structural dynamics of stiffened and inhomogeneous plates • Localized modes: stiffened plates, steeldrum, piano soundboard • Acoustic radiation: influence of localization on directivity 1st BATWOMAN workshop August 25-27 2014
Geometric nonlinear vibrations (I):weakly nonlinear regimes • Model reduction for thin shells and nonlinear modes • Numerical calculation of nonlinear modes • Thin shells discretized using finite elements • Transition to turbulence in thin plates • Numerical characterization of the transition and experimental comparison • 2 bifurcations – 3 regimes • Influence of imperfections 1st BATWOMAN workshop August 25-27 2014
Geometric nonlinear vibrations (II):strongly nonlinear regimes • Wave turbulence in thin plates • Experimental study: • effect of damping on the power spectra • 2D measurement by profilometry • Numerical study: • finite difference + conservative scheme in time • effect of anisotropy and plate defaults 1st BATWOMAN workshop August 25-27 2014
Numerical simulation of a piano • Nonlinear string dynamics – phantom partials • Numerical model of a nonlinear stiff stringusing a conservative scheme • Coupled to a complete piano model=> http://modelisation.piano.free.fr 1st BATWOMAN workshop August 25-27 2014
Numerical simulation of a piano SIMULATED RECORDED Note C#5 1st BATWOMAN workshop August 25-27 2014
PhD – ESR4 – BatwomanJin Jack TAN – ENSTA ParisTech Piano modeling: Complex boundary conditions for the strings, bridge motion and radiation of the structure
Purpose of the work – scientific context Improve a previous piano model by J. Chabassier (PhD 2012 ; supervisors: P. Joly and A. Chaigne) • Dynamics of strings:Allow a nonplanar motion through modification of the boundary conditions. First step: lumped bridge. 1st BATWOMAN workshop August 25-27 2014
Purpose of the work – scientific context 2. Dynamics of bridge and soundboard:Allow flexural and torsional motion of the bridge (and ribs). 3. Radiation of the piano (mostly experimental)To be done at MDW (secondment) during the 2nd year of the PhD under supervision of A. Chaigne. 1st BATWOMAN workshop August 25-27 2014
ER2: Portability and mutual applications of developed simulation methopds • Planned starting month : M24 September 2015 (rather than M17 February 2015 as initially planned) • Supervision: Cyril Touzé (ENSTA) and Stefan Bilbao (Univ. Edinburgh) • To discuss together: • Codes that could be tested and applied to another application • sound field synthesis in room acoustics • passenger car acoustics using wave methods (mid frequency range) • nonlinear vibrations • … • Profile of the ER? Dissemination strategy? 1st BATWOMAN workshop August 25-27 2014