ABSTRACT
Convection traditionally refers to heat transfer associated with a žuidwhichisinmotion.Whenthežuidmotioniscausedbyan externalagency,forexample,afanora“wind,”theconvection istermedasforcedconvection.Infreeconvection,incontrast, žuidmotionispredominantlyduetobuoyancyforcescausedby densitydi§erencesinthežuid;thedensitydi§erenceisgenerally duetovariationsoftemperatureorvariationsofconcentration of species or both.
