Aparalleldirect-forcingfictitiousdomainmethodisappliedinfully-resolvednumericalsimulationsofparticle-ladenturbulentflowsinasquareduct.Theeffectsoffinite-sizeheavyparticlesonthemeansecondaryflow,themeanstreamwisevelocity,theroot-mean-squarevelocityfluctuation,andtheparticleconcentrationdistributionareinvestigatedatthefrictionReynoldsnumberof150,theparticlevolumefractionof2.36%,theparticlediameterof0.1ductwidth,andtheShieldsnumberrangingfrom1.0to0.2.Ourresultsshowthattheparticlesedimentationbreakstheup-downsymmetryofthemeansecondaryvortices,andresultsinastrongersecondary-flowcirculationwhichtransportsthefluidsdownwardinthebulkcenterregionandupwardalongthesidewallsatalowShieldsnumber.Thiscirculationhasasignificantimpactonthedistributionofthemeanstreamwisevelocity,whosemaximumvalueoccursinthelowerhalfduct,unlikeintheplanechannelcase.Theflowresistanceisincreasedandtheturbulenceintensityisreduced,astheShieldsnumberisdecreased.Theparticlesaccumulatepreferentiallyatthefacecenterofthebottomwall,duetotheeffectofthemeansecondaryflow.Itisobservedthatthecollisionmodelhasanimportanteffectontheresults,butdoesnotchangetheresultsqualitatively.
