Pipesarewidelyusedtotransportgas,oilandwaterinindustries.Dragreductioninpipesisanincreasinglyconcernedproblemtosaveenergy.Someresearcheshaveindicatedthatthenon-smoothsurfacewithspecialstructurescanreduceflowloss.Inthispaper,anexperimentalinvestigationhasbeenperformedontheeffectsofakindofsurfacegrooveonthedraginbothrectangularandcircularductatdifferentReynoldsnumbers.Intheexperimentoftherectangularduct,totalpressureatbothinletandoutletweremeasured.Staticpressureonthewallwasmeasuredonthesurfacewithsmoothandgroovedfilmrespectively.Inthecircularduct,aboundarylayerpressureprobewasusedtomeasurethetotalpressuredistributionatbothinletandoutlet.Fourtapsatinletandoutletwereusedtomeasurestaticpressure.Thelosscoefficientisusedtoevaluatetheeffectsofthesurfacegrooveondragreduction.TheexperimentwasconductedwiththeReynoldsnumberrangefrom1.28×10~4to2.57×10~4.Theresultshowsamaximumdraglossreductionofapproximately2.4%inrectangularductatReynoldsnumberof2.4×10~4.A10%reductionofpipepressurelossbygroovedsurfaceismeasuredincircularductataReynoldsnumberof3.0×10~5.
