Linearized Navier-Stokes solver for in-duct aeroacoustics GUNILLA EFRAIMSSON Department of Aeronautical and Vehicle Engineering KTH, Stockholm, Sweden
[email protected] Axel Kierkegaard, Wei Na, Mats Åbom, Ciarán O’Reilly, Susann Boij, Hans Bodén Outline • Tango-aspects • Linearized Navier-Stokes equations solver • Two tecases - Area expansion - Thick orifice • Conclusions and future work Tango setting Q˙ 0 Unsteady heat release Generation of sound waves Perturbation flow & flame Pressure Oscillation p0 Study the coupling sound , flow and heat release using linearized Navier-Stokes equations Generation and Propagation of Sound • Generation Fans, rotor-stator interaction, constrictions, jets, combustion - Acoustic analogies, direct methods - Transient phenomena è transient simulations (LES,, DES, uRANS) or scaling laws • Propagation Free air, pipes, influence of flow, influence of solid surfaces (shielding), coupling of sound and flow (whistling, damping of sound), duct terminations - Linear equations in time or frequency domain: Helmholtz equation, wave equation, linearized Euler equations etc Propagation of sound in ducts with constrictions Straight cylindrical duct with orifice plate Turbulent meanflow Incoming waves are partly reflected and partly transmitted Reflections from downstream obstacles (or boundary conditions) Zone I Zone III Zone IV Zone II x 0 1 = x2 = 0 Propagation of sound in ducts with constrictions Straight cylindrical duct with orifice plate Turbulent meanflow Incoming waves are partly reflected and partly transmitted Reflections