Axisymmetric turbulent boundary layer on the cylindrical portion of an afterday test model

Krishnan, V (1985) Axisymmetric turbulent boundary layer on the cylindrical portion of an afterday test model. Technical Report. National Aeronautical Laboratory, Bangalore, India.

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    Abstract

    Experiments were conducted to study the characterstics13; and the growth of a11 axisymmetric turbulent boundary layer on tiie central cylindrical portion of a model in the presence of a circular arc forebody, an afterbody and a high pressure cold air jet issuinig from the base, An 8Omm m. max. dia model was tested at the freestream velocities of 12.8 and 21.5 m/Sec and at jet pressure ratios of 1.0 (jet- off),26 and 1,54. This report describes the results for the experimental study. The effect of jet is to increase the free streedy velocity and to create a slight favourable pressure gradient on the central cylinuer. The skin friction was obtained using the measured velocity profile.suggested by Luxton et.a1 can be used for the present type of situation although there is slight variation of the skin friction in the axial direction. The boundary layer grows in the axial direction aid tile displacement and mometum thickness depend upon tile measurement station and test conditions. The variation of shape factor is small. It is of the order of unity and frictional reynolds number .The velocity profiles snow the substantial ammount of the logrithmic region when plotted in the two dimensional wall law and defect law coordinates. the slope (A) is found to be universal and approimately equal to 5.5 as suggested by different investigators.but the intercepts (Bamp;D)are riot universal and depend upon the axial location of the measurement station and conditions.

    Item Type: Proj.Doc/Technical Report (Technical Report)
    Uncontrolled Keywords: Axisymmetric turbulent boundary layer;Afterbody test model;Jet effects
    Subjects: ENGINEERING > Fluid Mechanics and Thermodynamics
    Division/Department: Fluid Dynamics
    Depositing User: M/S ICAST NAL
    Date Deposited: 25 Sep 2006
    Last Modified: 24 May 2010 09:50
    URI: http://nal-ir.nal.res.in/id/eprint/2780

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