Mid-Term Report Fellow’s Presentation Jonathan Tournadre Keele University 18/09/2014 Mid-Term Report Fellow’s Presentation Jonathan Tournadre

Outline Introduction of the fellow 1 Introduction of the fellow 2 Research task motivation and objectives 3 Research achievements and future plans 4 Technical and complementary skills development 5 Networking

Numerical study of perforated plates with grazing and bias flow Who am I? PhD student enrolled at the KU Leuven, in the Mechanical Engineering faculty. Work at Siemens (former LMS International), in the 3D simulation division. Part of the TANGO Project on Research Task 1.3 Numerical study of perforated plates with grazing and bias flow

Resonator array to attenuate tonal noise, combustion chamber orifices Motivations and goals of research task Better understand the physics of sound-flow interaction for perforates Gain better modeling/simulation capability for structures with perforations Applications: Resonator array to attenuate tonal noise, combustion chamber orifices Figure: Orifice structures in gas turbine. Figure: Honeycomb structure of SDOF locally reacting liner.

Motivations and goals of research task Some of the challenges: Various flow conditions: Grazing flow, bias flow, mixed. Work done previously Scale-resolving simulations such as Direct Numerical Simulation (DNS) Semi-empirical models Computationally costly Limited validity range

Accurate simulation of flow/sound interaction for perforate structures From the comprehension of local phenomena … Increased reliability in impedance modelling Numerical Hybrid Methodology Development of Linearized Navier Stokes Equations solver Parametric studies & Impedance measurement techniques Different scales To the application for complex geometries Implementation in lower accurate solver Impedance boundary condition in Convected Helmholtz solver

Accurate simulation of flow/sound interaction for perforate structures To model the acoustic propagation in presence of a mean flow, using a general operator (LEE/LNSE). Continuous high-order Finite Element method (pFEM) code Frequency domain, 2D Linearized Navier-Stokes Eq. (can be reduced to LEE) Matlab® prototype code, Higher-order Lobatto polynomial shape functions.

Numerical hybrid methodology Y-velocity field for base flow CFD CFD mesh Choice of models RANS computation Export base flow LNSE pFEM Linearized Navier-Stokes Eq. model simulation Numerical CAA hybrid methodology Post-processing Impedance value estimation In-situ technique Eduction method Two-port method Acoustic energy dissipation and production

Research achievements - Study on 2D slit resonator Dedicated measurement campaign on 2.5D slit resonator, compared to two LNSE numerical tools. Gain lacking database for quasi 2D rectangular orifices, Gain experiences in aero-acoustics numerical tools, Compare different impedance characterization approaches.

Research achievements - Study on 2D slit resonator Figure: CAD model of the test section (left) and pictures of the opened test object (top right) and the test object built into the rig (bottom right).

Research achievements - Study on 2D slit resonator 90 mm Computational Fluid Dynamics extended domain Acoustic computational domain Figure: Schematic overview of the geometry under consideration.

Research achievements - Study on 2D slit resonator Cases done: Continuous pFEM code Discontinuous Galerkin method code Experimental campaign In-situ x / Lumped model Eduction method Table: Summary of cases investigated. For Mach numbers M = 0, 0.025, 0.05, 0.075, 0.1. Over the frequency range [200 Hz – 2000 Hz].

Research achievements - Study on 2D slit resonator Figure: Absolute value of the scatter matrix coefficients for different mean flow Mach numbers.

Research achievements - Study on 2D slit resonator Figure: Normalized resistance (top) and reactance (bottom) for different grazing flow velocities.

Future plans Work on impedance boundary conditions (for convected Helmholtz equation type solver) Application case to a global system Further development on the Linearized Navier-Stokes Eq. solver

Technical trainings, lectures and workshop Training / Workshop description Date Place VKI lecture series “Accurate and efficient aero-acoustic prediction approaches for airframe noise March 2013 VKI, Brussels - Belgium VKI lecture series “Modelling, measurement and control of ventilation and cooling noise” April 2013 Non normal and nonlinear effects workshop June 2013 TUM, Munich -Germany ISAAC course September 2013 KUL, Leuven - Belgium Experimental methods in thermo-acoustics April 2014 KTH, Stockholm - Sweden Aero-acoustics in confined flows of low Mach number IITM, Chennai - India Experimental NVH training June 2014 LMS, Leuven - Belgium Analytical methods in thermo-acoustics September 2014 Keele University, UK * Done in the frame of TANGO

Complementary skills (research management and communication) Training /workshop description Date Place Presentation skills March 2013 LMS, Leuven - Belgium Outreach Training (1) September 2013 Deutsches Museum, Munich -Germany Effective communication training January 2014 Gender Issue workshop April 2014 KTH, Stockholm -Sweden * Done in the frame of TANGO

Training /workshop description Conferences Training /workshop description Date Place 20st AIAA/CEAS Aeroacoustics Conference June 2013 Berlin, Germany 21st AIAA/CEAS Aeroacoustics Conference June 16-20 2014 Atlanta, USA “Combined Numerical and Experimental Study of a Slit Resonator Under Grazing Flow” * Done in the frame of TANGO

Networking opportunities Inside the project Part of the vibro-acoustic research group at KUL Secondment to be defined Extra networks Member of Belgian Acoustical Society (ABAV) and of B-YAN (Belgian Young Acousticians Network) Member of Marie Curie Alumni Association (MCAA)

Thank you for your attention. Contact: Jonathan Tournadre jonathan.tournadre@siemens.com