Wall-pressure and PIV analysis for microbubble drag reduction investigation

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dc.contributor.advisor Hassan , Yassin A . en_US
dc.contributor.committeeMember Annamalai , Kalyan en_US
dc.creator Dominguez Ontiveros , Elvis Efren en_US
dc.date.accessioned 2005 -11 -01T15 :46 :29Z
dc.date.accessioned 2014 -02 -19T19 :22 :19Z
dc.date.available 2005 -11 -01T15 :46 :29Z
dc.date.available 2014 -02 -19T19 :22 :19Z
dc.date.created 2004 -08 en_US
dc.date.issued 2005 -11 -01T15 :46 :29Z
dc.identifier.uri http : / /hdl .handle .net /1969 .1 /2582
dc.description.abstract The effects of microbubbles injection in the boundary layer of a turbulent channel flow are investigated . Electrolysis demonstrated to be an effective method to produce microbubbles with an average diameter of 30 ? ?m and allowed the placement of microbubbles at desired locations within the boundary layer . Measurement of velocity fluctuations and the instantaneous wall shear stress were carried out in a channel flow facility . The wall shear stress is an important parameter that can help with the characterization of the boundary layer . This parameter can be obtained indirectly by the measurement of the flow pressure at the wall . The wall shear stress in the channel was measured by means of three different independent methods : measurement of the pressure gradient by a differential pressure transducer , Particle Image Velocimetry (PIV ) , and an optical wall shear stress sensor . The three methods showed reasonable agreement of the wall shear stress values for single -phase flow . However , differences as skin friction reductions were observed when the microbubbles were injected . Several measurements of wall -pressure were taken at various Reynolds numbers that ranged from 300 up to 6154 . No significant drag reduction was observed for flows in the laminar range ; however , a drag reduction of about 16 % was detected for turbulent Reynolds numbers . The wall -pressure measurements were shown to be a powerful tool for the measurement of drag reduction , which could help with the design of systems capable of controlling the skin friction based on feedback given by the wall -pressure signal . The proposed measurement system designed in this work has capabilities for application in such diverse fields as multiphase flows , drag reduction , stratified flows , heat transfer among others . The synchronization between independent systems and apparatus has the potential to bring insight about the complicated phenomena involved in the nature of fluid flows . en_US
dc.format.extent 6644628 bytes
dc.format.medium electronic en_US
dc.format.mimetype application /pdf
dc.language.iso en _US en_US
dc.publisher Texas A &M University en_US
dc.subject drag reduction en_US
dc.title Wall -pressure and PIV analysis for microbubble drag reduction investigation en_US
dc.type Book en
dc.type.genre Electronic Thesis en_US
dc.type.material text en_US
dc.format.digitalOrigin born digital en_US

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Wall-pressure and PIV analysis for microbubble drag reduction investigation. Available electronically from http : / /hdl .handle .net /1969 .1 /2582 .

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