简介：Onthehypothesisthattheturbulentflowispracticallynotaffectedincharacterbypulsationoftheflow,theformulaforsoundpressurelevelofpulsedjetnoiseisobtainedin90°directionand1meterawayfromthenozzle.Thesteadyjetnoiseis,then,aspecialcasewhenthepulsatingfrequencyiszero.Theresultsagreewellwithexperiments.

简介：Onthebasisofspectrummomentdescriptionofasignal,evolutionaryvectorisdeveopedtodescribeslowlytime-varyingnoiseprocesses.Itdescribesthemaintime-varyingpropertiesofasignal.Applicationstoaircraftflying-overnoisearepresented.

简介：Justfortyyearsago,ZwikkerandKosten‘sclassicalwork"SoundAbsorbingMaterials"waspublishedandthetheoreticalfoundationofsoundabsorbingmateri-alswaslaid.AndMechel‘smonograph"Schallabsorber"isanimportantdevelop-ment.Thebookconsistsofthreevolumes.Volumeoneisoutersoundfield,thatis,interactionbetweensoundfieldandsoundabsorber;volumetwoisinternalsoundfield,orthestructureandapplicationofsoundabsorber;volumethreeiscomputerprogram,asupplementaryvolume.Volumeoneisnowpublished.The

简介：Fromtheevolutionaryvectordeacriptionofslowlysime-varyingnoiseprocess,ameasurefornon-stationarityisdeveloped.Itincludesboththenon-stationaritiesofpowerandofspectrumshape.Asasingleparameter,itisacomparablequantityfordifferentprocesses.Applicationtotheanalysisofprecisegearboxisprescnted.

简介：Anewapproachtothetheoryoffinite-amplitudestandingwavesinproposed,andfoumulasofsteadywaveformsarederivedfromthefundamentalequationsofhydrodynamios,asanendeavortosettlethelong-timedisputablesituation.