Aeroacou oacoust stics ics and CFD-base sed d wavenumb enumber er analys ysis is towards ds aero-vibr vibroa oaco coustics ustics Fred Mendonça donça, CD-adapco dapco Cont ntinuing nuing Challen llenge ges s in n Aeroac oacou oustics stics Simulation mulation Curre rrent nt Prac actices ices and nd Future ture Prospects rospects STAR AR Korea rea Conf nfere erenc nce e 2012
HVAC, C, ECS, S, Duct t ventilation ilation and disc schar arge ge
Ext xtern ernal al Aeroa oaco coust ustic ic Excitation itation Surface FFT (dB) at 500Hz (top) and 1000Hz (bottom)
Airframe frame and Jet et noise se
Turbo bo compressor ressor Noise se
HVAC C – blower er, , distr tribu ibutor or, , ducts
Pipe e singi ging
Sunroo oof/side f/side-windo window w buffeti eting g – real l vehicle le effects ts – Wall compl mplian ance ce effec ects ts • Full FSI of comp mplian ant t wal walls s (below left) t) • Corre relati tions ns for wal wall comp mplianc nce e (below right ht) – Changes es natural l cavity ity freq equen ency – Qualit lity Fac actor or causes ses damping ing – Leaka kages ges Alumin iniu ium MDF Persp rspex Uncorrected Correlated
Hydroac oacousti oustics / cavita tatio tion n noise se
Aeroa oaco coust ustics ics requir iremen ements ts for vibro-ac acoustics? oustics? Ae Aeroacous roacoustics ics Sim Simulations lations Optio ions ns Steady ady stat ate Transient ansient Synt nthe hesized ized Broad oadban band d LES LES Fluc uctua uatio ions ns SNGR Correla rrelatio ions ns DES LEE LEE CURLE surf urfac ace Trans ansien ient RANS AN volume Lille ley PROUDMAN olume Point int/Sur Surfac ace e FFTs and d iFFTs GOLD LDST STEI EIN 2D-ax axi Expor port to o Auto o and d Cros oss Spec ectra ra – cohe here renc nce e and d phas ase Propa opagat gation ion code des 1D (and nd 2D) ) Wavenum enumber ber analy alysis is Mesh Freq eque uenc ncy Cut-off FW FW-H Direc ect Noise Prop opaga agatio ion Expor port com ommerc rcial ial prop opaga agation ion codes odes
Focus s on Transient ansient and Aeroa oacoustics coustics – LES-type turbulence model • DES (opti tions ons of Spalart-Allmar maras as, , k- ε, k - ωSST ) • DES advecti tion n scheme blendi ding ng • Full LES (wal wall resolved ed or under er-re resol solved d ! ) – Advanced wall treatment • y+ inse nsens nsitive – Non-reflecting conditions for • Inflo low and outfl flow bounda dari ries es – Full Compressibility • Intera eracti ction n bet etween the flow and acoustics stics – Espec ecia ially lly for cavi vity ty reson sonanc ance e – Very efficient commercial transient solver • 2 nd nd order r space and time discreti scretisati sation – Spectral Analysis • FFT and iFFTs at points nts and surfac aces es • Auto and Cross ss spectra ctra – coherence nce and phase se • Frequ quency ncy and Wave Number r Fouri rier r analysis sis
FFT post-pr proc ocess essin ing g (point) oint) – Monitor point in mirror wake STAR Experiment – Tail-off in predicted spectrum at mesh cut-off frequency of ~1000 Hz
Direct ect Propagat pagation ion in STAR-CC CCM+ – Mesh requirement • 20 cells per acoustic wavelength ( λ = c / f ) – In ambient conditions, you need cells of ~15mm to propagate a signal at 1000Hz – Domain size = 1000D, (~10 λ ) – Non-reflective in/outflow boundaries
Propagat pagation ion – FW FW-H H and 3 rd rd party ty code expor ort – STAR results capture the acoustic sources for propagation via • Ffowcs Williams-Hawki wkings ngs (far-field eld pro ropagati tion n of compact sources witho thout t int nternal rnal refl flecti ctions) ons) – STAR offers coupling to 3 rd party propagation codes: • FFT, ACTRAN AN • LMS, , Virtu tual.La al.Lab.A b.Acou oustic tics 500 0 Hz 100 0 Hz • ESI, VA-One – VibroAcoustics • Using ng FVS in STAR-CC CCM+ • Export t to SEA and FEA 3150 50 Hz Over erall all
Introdu oduction ction to 1D (line) ine) WaveNumber mber Analysis ysis Bremne mner and Wilby AIAA-200 2002-255 2551 Φ c (k, ѡ ) Φ c (k, ѡ ) k k Φ 0 (k, ѡ ) Φ 0 (k, ѡ ) k c = ѡ /U c k c = ѡ /U c k 0 = ѡ /c 0 k 0 = ѡ /c 0 ѡ ѡ Wave venumber (rad/m) /m)
Idealised side-view mirror
South utham ampt pton on Uni Univer ersit ity y Setu etup DAR ARP acousti ustic tun unnel nel open en secti ction on 40ms ms -1 open en jet et Mirror or height ight is 15cm cm Re = 2x10 5 based ed on mirror or diame meter r (half f dimen mensi sion ons s of the e origina inal l Daimle ler r exper perimen iment AI AIAA AA-1999 999-1895 895) 11 million on cells ls Refined wake and “side - glass” 2mm m resolution olution CFD previously viously validat ated ed – AIAA-2011-2843
1D wave number er analysis lysis on attac ached hed and separat arated ed zones es a + a - u - a + a - u +
2D wave number er analysis lysis at disc scre rete e freque uencies cies Convectiv ctive e ridge ge Ac Acoustic tic circl cle
Separat arating g the acoustic stic conten ent
Total al and acoust stic ic power input ut to vibrat ration ion analysis ysis
Next xt Steps ps Extens enstion tion to 2D WNA A in STAR- CCM+ v∞ Det etail ailed ed Valid idat ation on from Southam thampton on Exper erim imen ent – See AIAA Aeroacoustics Conference 2012 Validation idation on produc uction tion Vehicles es CFD gene nera rated d acous oustic tics driving ing – Propagating acoustics – Diffuse acoustics in n SEA/ A/FEA FEA vibroac oacous oustic tics models for interior erior noise transm ansmission. ion. THANK NK YOU for your ur KIND D ATTE TENTI NTION ON
Recommend
More recommend
