Dryden Wind Turbulence Model (Continuous)翻译

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1、AerospaceBlockset™DrydenWindTurbulenceModel(Continuous)Generatecontinuouswindturbulence连续风紊流withDrydenvelocityspectra德莱顿速度谱LibraryEnvironment/WindDescriptionTheDrydenWindTurbulenceModel(Continuous)blockusestheDrydenspectralrepresentation德莱顿谱表示toaddturbulencetotheaerospacemodelbypassingband-l

2、imitedwhitenoisethroughappropriateformingfilters将带限白噪声通过适当的成形滤波器.Thisblockimplementsthemathematicalrepresentation数学表达intheMilitarySpecificationMIL-F-8785CandMilitaryHandbookMIL-HDBK-1797.Accordingtothemilitaryreferences,turbulenceisastochasticprocessdefinedbyvelocityspectra紊流是由速度谱定义的随机过程.For

3、anaircraftflyingataspeedVthroughafrozenturbulencefieldwithaspatialfrequencyofΩradianspermeter,thecircularfrequencyωiscalculatedbymultiplyingVbyΩ.Thefollowingtabledisplaysthecomponentspectrafunctions:Thevariablebrepresentstheaircraftwingspanb为翼展.ThevariablesLu,Lv,Lwrepresenttheturbulencescale

4、lengths标尺长度.Thevariablesσu,σv,σwrepresenttheturbulenceintensities紊流强度.Thespectraldensitydefinitionsofturbulenceangularrates紊流角速率的谱密度定义aredefinedinthespecificationsasthreevariations,whicharedisplayedinthefollowingtable:Thevariationsaffectonlythevertical(qg)andlateral(rg)turbulenceangularrates

5、.Keepinmindthatthelongitudinalturbulenceangularratespectrumisarationalfunction.Therationalfunctionisderivedfromcurve-fitting曲线拟合acomplexalgebraicfunction,nottheverticalturbulencevelocityspectrum,Φw(ω),multipliedbyascalefactor.Becausetheturbulenceangularratespectracontributelesstotheaircraftg

6、ustresponsethantheturbulencevelocityspectra,itmayexplainthevariationsintheirdefinitions.Thevariationsleadtothefollowingcombinationsofverticalandlateralturbulenceangularratespectra:VerticalLateralΦq(ω)Φq(ω)−Φq(ω)−Φr(ω)Φr(ω)Φr(ω)Togenerateasignalwiththecorrectcharacteristics,aunitvariance,band

7、-limitedwhitenoisesignalispassedthroughformingfilters.Theformingfiltersarederivedfromthespectralsquarerootsofthespectrumequations.Thefollowingtabledisplaysthetransferfunctions:Dividedintotwodistinctregions,theturbulencescalelengthsandintensitiesare