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1、第3O卷第2期力學(xué)季刊VoI.30No.22009年6月CHINESEQUARTERLYOFMECHANICSJune2009方腔雙壁反向驅(qū)動流渦結(jié)構(gòu)演化的數(shù)值模擬何士華,張立翔,徐天茂(1.昆明理工大學(xué)水力工程系,昆明650051;2.昆明理工大學(xué)工程力學(xué)系,昆明650051)摘要:采用微分求積法計(jì)算分析了不同雷諾數(shù)的二維方腔驅(qū)動流渦結(jié)構(gòu)特性。數(shù)值模擬著重研究了雷諾數(shù)從0.Ol到1000變化對方腔雙壁反向驅(qū)動流渦結(jié)構(gòu)演化的影響,給出了渦演化過程的流型圖和分叉圖。結(jié)果表明,當(dāng)雷諾數(shù)接近0時(shí),腔內(nèi)流動呈現(xiàn)對稱的渦結(jié)構(gòu)流型;隨
2、著雷諾數(shù)增加,子渦的大小和中心位置發(fā)生變化,鞍點(diǎn)始終位于方腔的中心,腔內(nèi)流動形成非對稱的斜扭流型;當(dāng)雷諾數(shù)增大到某一臨界值后,單一大渦占住整個(gè)方腔,大渦的形狀變得更圓;如果雷諾數(shù)繼續(xù)增加,方腔左上角和右下角同時(shí)出現(xiàn)二級渦,大渦中心始終位于方腔中心不變。關(guān)鍵詞:方腔驅(qū)動流;Navier—Stokes方程;渦結(jié)構(gòu);微分求積法中圖分類號:TB126文獻(xiàn)標(biāo)識碼:A文章編號:0254—0053(2009)02—176.7NumericalSimulationofVortexStructureEvolutioninaSquareCav
3、itywithTwoOppositeMovingWallsHEShi.hua,ZHANGLi—xiang,XUTian—mao(1.DepartmentofHydraulicEngineering,KunmingUniversityofScience&Technology,Kunming650051,China;2.DepartmentofEngineeringMechanics,KunmingUniversityofScience&Technology,Kunming650051,China)Abstract:Thevo
4、rtexstructureoftwodimensionalsquarecavitydrivenflowatdifferentReynoldsnumberwascalculatedbyusingdifferentialquadraturemethod.ThenumericalsimulationfocusesoninvestigatingtheeffectsofReynoldsnumberrangingfrom0.01to1000onvortexstructureevolutionoftheflowinasquarecavi
5、tywithtwooppositemovingwalls.Theflowpatternsandbifurcationdiagramsweredeter-mined.Thenumericalresultsshowthattheflowinthecavitytakesontheflowpatternofsymmetricvor—texstructurewhenReynoldsnumberapproaches0.WithReynoldsnumberincreasing,thesizesandcen—terpositionsoft
6、hesub—eddiesappeartobeaffected,whereasthesaddlepointisstilllocatedatthecavitycentre,resultinginanasymmetricskewedflowpatterninthecavity.Itobservesthatonelargevortexoccupiestheentirecavity;theshapeofthelargevortexbecomesmorecircularafteracriticalvalueofReynoldsnumb
7、eriSexceeded.IfReynoldsnumberisincreasedfurther,twosecondaryeddiesemergesim-ultaneouslyontheupperleftcornerandthelowerrightcorner.Thecentreofthelargevortexisinvaria-blylocatedatthecavitycentre.Keywords:cavitydrivenflow;Navier.Stokesequation;vortexstructure;differe
8、ntialquadraturemethod方腔驅(qū)動流包含許多復(fù)雜的流動現(xiàn)象,諸如不同類型和不同尺度的渦結(jié)構(gòu)、暫態(tài)和湍流現(xiàn)象、各種不穩(wěn)定性等,這些重要的流動現(xiàn)象與很多工程應(yīng)用密切相關(guān)。同時(shí),方腔驅(qū)動流因其幾何形狀相對簡單而被廣泛用于驗(yàn)證和比較粘性不可壓縮流動不同算法的有效性。收稿日期:2008—09-18