Hydrodynamic stability-Jan

《Hydrodynamic stability-Jan》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、HydrodynamicstabilityJanPralitsDepartmentofCivil,ArchitecturalandEnvironmentalEngineeringUniversityofGenoa,Italyjan.pralits@unige.itGiugno13-15,2012CorsodidottoratoinScienzeeTecnologieperl'Ingegneria(STI):FluidodinamicaeProcessidell'IngegneriaAmbientale(FPIA)JanPralits(UniversityofGenoa)Hydro

2、dynamicstabilityGiugno13-15,20121/51OutlineCourseoutlineTopic:Hydrodynamicstability(Linear,temporal,parallelshear ows)Hours:10Lectures:AulaA12(Ex-DISEG)Wednesday13/069-11&14-16Thursday14/069-11&14-16Friday15/069-11&11-13(Exerciseoptional)PleasebringyourlaptopforthenumericalanalysisCredits:2Co

3、ntent:1Introduction2Denitions3Inviscidanalysis4Viscousanalysis5Exercises:analytical&numericalBook:SchmidP.J.&HenningsonD.S.,StabilityandTransitioninShearFlows,SpringerJanPralits(UniversityofGenoa)HydrodynamicstabilityGiugno13-15,20122/51IntroductionHydrodynamicstabilityHydrodynamicstabilityt

4、heoryisconcernedwiththeresponsoflaminar owtoadisturbanceofsmallormoderateamplitude.The owisgenerallydenedasStable:Ifthe owreturnstoitsoriginallaminarstate.Unstable:Ifthedisturbancegrowsandcausesthelaminar owtochangeintoadierentstate.Stabilitytheorydealswiththemathematicalanalysisoftheevolut

5、ionofdisturbancessuperposedtoalaminarbase ow.Inmanycasesoneassumesthedisturbancestobesmallsothatfurthersimplicationscanbejustied.Inparticular,alinearequationgoverningtheevolutionofdisturbancesisdesirable.Asthedisturbancevelocitiesgrowaboveafew%ofthebase ow,nonlineareectsbecomeimportantandl

6、inearequationsnolongeraccuratelypredictthedisturbanceevolution.Althoughthelinearequationshavealimitedregionofvaliditytheyareimportantindetectingphysicalgrowthmechanismsandidentifyingdominantdisturbancetypes.JanPralits(UniversityofGenoa)HydrodynamicstabilityGiugno13-15,20123/51IntroductionReyn

7、oldspipe owexperiment(1883)Original1883appartusDyeintocenterofpipeCriticalRe=13:000LowertodayduetotracJanPralits(UniversityofGenoa)HydrodynamicstabilityGiugno13-15,20124/51IntroductionHistoryofshear owstabilityandtransitionReynoldspipe owexp