ABSTRACT
Laminarandturbulentflow.Whenfluidparticlesmoveinsmoothpaths withoutlateralmixing,theflowissaidtobelaminar.Viscousforcesdominate otherforcesinlaminarflowanditoccursonlyatverysmalldepthsandlow velocities.Itisseeninthinfilmsoverpavedsurfaces.LaminarflowisidentifiedbytheReynoldsnumberRe=pvylp,wherepisthedensityandp,the viscosity.(Forlaminarflowinopenchannels,Reislessthanabout500.)As thevelocityanddepthincrease,Reincreasesandtheflowbecomesturbulent, withconsiderablemixinglaterallyandverticallyinthechannel.Nearlyall openchannelflowsareturbulent.
