軸對稱射流中擬序結(jié)構(gòu)演變的數(shù)值模擬.pdf

1、浙江大學(xué)碩士學(xué)位論文軸對稱射流中擬序結(jié)構(gòu)演變的數(shù)值模擬姓名：劉中秋申請學(xué)位級別：碩士專業(yè)：流體機械及工程指導(dǎo)教師：林建忠2001.1.11、領(lǐng)垃大學(xué)碩士學(xué)f皇論芝2001lNumericalSimulationoftheEvolutionofCoherentStructuresinanaxisymmetricjetflowABSTRACTInthisthesis，theresearchoncoherentstructuresinaJet

2、shearlayerisreviewedThevortexdynamicsandthevortexmethodareintroducedcomprehensivelyEmployingthethree—dimensionalvortexmethod，anaxisymmetricincompressibleviscidjetflowissimulated，andthetemporalevolutionofthespanwisevortic

3、esinthejetflowIsindicatedInordertoinvestigatetheeffectofviscosityonvorticesinthejet，vortexroll—upisstudiedunderthreedifferentconditions(Re=2103、Re=2104andinviscid)Theresultsshowthatviscositysuppressesvortexroll—upandthel

4、argertheRenumberis，thesmallerthiseffectisWhenRe=2xl0’thevorticitydiffusionunderviscosityiscomparati、，elyobviousandthevortexroll—upisrelativelySlOW、VhenRe=2104theeffectofviscosityonthevorticitydiffusionandvortexroll—upisr

5、athersmallduringthecomputingtime，extremelyapproachingtheresultofinviscidjetInaddition，theeffectsoftheinitialintensityofthesubharmonicperturbationandtheinitialphasedifferencebetweenthefundamentalperturbationandthesubharmo

6、niconeonvortexpairingarecarefullyinvestigatedThefollowingaretheconclusionsTheeffectoftheinitialintensityofthesubharmonicperturbationonvortexpairingisaccelerativeNamely，thelargertheinitialintensityis，thelargerthespeedofvo

7、rtexpairingisTheinitialdifference口betweenthefundamentalperturbationandthesubharmoniconehasastrongeffectonvortexpairingWhen口=O，vortexpairingOccursearliest；As8increases，thespeedofvortexpairingdecreases；When0=≈坦，vortexpairi

8、ngdoesnotOCCUr，andthebraidlegioncomesintobeingaSthedistancebetweenthetWollupvorticesincreasesAs口goesup，thedecreasespeedofthe、ortisityinthebraidregiongoesuptooWhen∥2，『，thespeedreachesitsmaximumAtthesametime，wealsofindthat