Study of the turbulent boundary layer on an afterbody

Krishnan, V (1989) Study of the turbulent boundary layer on an afterbody. Technical Report. National Aeronautical Laboratory, Bangalore, India.

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    Abstract

    Experiments were conducted to study the turbulent boundary layer on a circular arc boat-tailed afterbody model of 80 mm maximum diameter (D). Tests were conducted at free stream velocities upto 28 m/sec and without jet.13; There is a favourable pressure gradient (FPG) on the afterbody before strong adverse pressure gradient (APG) close to the base. The boundary layer thickness increases from 0.25 to 0.67 times local radius which may be considered thick especially close to the base. The parameters of the boundary layer remain fairly constant in FPG and change13; rapidly in APG. The mass flow shape factor is slightly greater than the predictions made using Green's relationship in APG.13; Mean velocity profiles have considerable portion of the logarithmic region when plotted in the two dimensional wall law coordinates. The log law constants have universal values and the wake component decreases in FPG. In APG, slope of the velocity profile when plotted in wall law coordinates increases. The intercept of the defect law is smaller compared to the two dimensional case in FPG. Normal static pressure measurements in the boundary layer show linear variations and it is such that the longitudinal pressure gradient is less at the edge of the boundary layer than at the model surface.

    Item Type: Proj.Doc/Technical Report (Technical Report)
    Uncontrolled Keywords: Afterbody;Turbulent boundary layer
    Subjects: AERONAUTICS > Aerodynamics
    Division/Department: Experimental Aerodynamics Division
    Depositing User: Mr. Ravikumar R
    Date Deposited: 13 Nov 2006
    Last Modified: 24 May 2010 09:53
    URI: http://nal-ir.nal.res.in/id/eprint/3421

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