Improvement in spatial resolution of background-oriented schlieren technique by introducing a telecentric optical system and its application to supersonic flow

A telecentric optical system is applied to the background-oriented schlieren (BOS) technique to improve accuracy, overcoming the drawbacks of conventional diverging light observation. This paper describes the optical arrangement and formula for telecentric BOS measurement and presents measurement results obtained by the colored-grid background-oriented schlieren technique to confirm the theoretical prediction. The application of the new approach for a large-scale supersonic wind tunnel test is reported.

[1]  R. Konrath,et al.  Telecentric lenses for imaging in particle image velocimetry: a new stereoscopic approach , 2002 .

[2]  Jürgen Kompenhans,et al.  Application of Quantitative Background Oriented Schlieren (BOS): Investigation of a Wing Tip Vortex in a Transonic Wind Tunnel , 2003 .

[3]  G. E. A. Meier,et al.  Computerized background-oriented schlieren , 2002 .

[4]  K. Onu,et al.  Schlieren measurement of axisymmetric internal wave amplitudes , 2003 .

[5]  Stuart B. Dalziel,et al.  Whole-field density measurements by ‘synthetic schlieren’ , 2000 .

[6]  Gary S. Settles,et al.  A comparison of three quantitative schlieren techniques , 2012 .

[7]  Erik Goldhahn,et al.  The background oriented schlieren technique: sensitivity, accuracy, resolution and application to a three-dimensional density field , 2007 .

[8]  G. Meier,et al.  Density measurements using the Background Oriented Schlieren technique , 2004 .

[9]  I. Znamenskaya,et al.  Study of shock-wave flows in the channel by schlieren and background oriented schlieren methods , 2012 .

[10]  M. Raffel,et al.  Recent developments in background oriented Schlieren methods for rotor blade tip vortex measurements , 2007 .

[11]  Joseph L. Sims,et al.  Tables for supersonic flow around right circular cones at zero angle of attack , 1964 .

[12]  Lakshmi Venkatakrishnan,et al.  Density field of supersonic separated flow past an afterbody nozzle using tomographic reconstruction of BOS data , 2009 .

[13]  Markus Raffel,et al.  Principle and applications of the background oriented schlieren (BOS) method , 2001 .

[14]  Masanori Ota,et al.  Three-Dimensional Density Measurement of Supersonic and Axisymmetric Flow Field by Colored Grid Background Oriented Schlieren (CGBOS) Technique , 2012 .

[15]  Shigeru Obayashi,et al.  Measurement sensitivity and resolution for background oriented schlieren during image recording , 2013, J. Vis..

[16]  M. Ota,et al.  Computed-tomographic density measurement of supersonic flow field by colored-grid background oriented schlieren (CGBOS) technique , 2011 .

[17]  M. Ota,et al.  COMPARISON BETWEEN CBOS (COLORED BACKGROUND ORIENTED SCHLIEREN) AND CGBOS (COLORED-GRID BACKGROUND ORIENTED SCHLIEREN) FOR SUPERSONIC FLOW , 2012 .