Development of a Quantitative Schlieren Technique: BOS

Venkatakrishnan, L (2004) Development of a Quantitative Schlieren Technique: BOS. Project Report. National Aerospace Laboratories, Bangalore.

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    Abstract

    A new technique making use of the recent advances in CCD technology and fast processors to obtain quantitative Schlieren of density fields in high-speed flows requiring only a digital camera was proposed by Meier (1999) called Background Oriented Schlieren. This report details the implementation of this technique to obtain density and its validation on an axisymmetric supersonic flow over a 150 cone. Comparisons with cone tables show excellent agreement. Measurements were also made on an axisymmetric converging nozzle (Mj=1) operating at moderately and highly expanded values of nozzle pressure ratios. The validation of the Filtered Back Projection Tomography (FBPT) used in this technique was done by extracting the central plane of a 4-jet configuration. Density fields for two nozzle expansion ratios are presented. The study shows that meaningful quantitative data can be extracted using minimal hardware with this technology.

    Item Type: Proj.Doc/Technical Report (Project Report)
    Uncontrolled Keywords: Quantitative Schlieren, Density measurements, BOS, Cone-cylinder, Underexpanded jet, Supersonic flow
    Subjects: AERONAUTICS > Aerodynamics
    Division/Department: Experimental Aerodynamics Division
    Depositing User: Smt Bhagya Rekha KA
    Date Deposited: 24 Aug 2011 13:41
    Last Modified: 24 Aug 2011 13:41
    URI: http://nal-ir.nal.res.in/id/eprint/9928

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