Three-dimensional density measurement of unsteady flow field around a sphere is carried out in the ballistic range at Institute of Fluid Science, Tohoku University. Simultaneous multi-angle measurement system using twelve digital cameras is installed in the test chamber of the ballistic range to achieve the three-dimensional density measurement. The Colored-Grid Background Oriented Schlieren (CGBOS) technique using colored-grid background is utilized for the reconstruction of density. The Mach number of the sphere is set to 1.5. The short pulse LEDs to illuminate the backgrounds are also installed in the chamber to capture the unsteady flow field around a flying sphere. Three-dimensional density distribution around a sphere is successfully reconstructed.
References
[1]
Rausch, V.L., McClinton, C.R. and Crawford, J.L. (1997) Hyper-X: Flight Validation of Hypersonic Airbreathing Technology. ISABE, 97-7024.
Carlson, H.W. (1964) Correlation of Sonic-Boom Theory with Wind-Tunnel and Flight Measurements. NASA Technical Report NASA TR R-213.
[4]
Settles, G.S. (1995) Full-Scale Schlieren Flow Visualization. The 7th International Symposium on Flow Visualization, Seattle, 11-14 September 1995, 2-13.
Leopold, F., Simon, J., Gruppi, D. and Schäfer, H.J. (2006) Recent Improvements of the Background Oriented Schlieren Technique (BOS) by Using a Colored Background. International Symposium on Flow Visualization, Göttingen, ISFV12-3.4, 1-10.
[7]
Venkatakrishnan, L. and Meier, G.E.A. (2004) Density Measurements Using the Background Oriented Schlieren Technique. Experiments in Fluids, 37, 237-247.
https://doi.org/10.1007/s00348-004-0807-1
[8]
Ota, M., Hamada, K., Kato, H. and Maeno, K. (2011) Computed-Tomographic Density Measurement of Supersonic Flow Field by Colored-Grid Background Oriented Schlieren (CGBOS) Technique. Measurement Science and Technology, 22, 1-7. https://doi.org/10.1088/0957-0233/22/10/104011
[9]
Ota, M., Kurihara, K., Aki, K., Miwa, Y., Inage, T. and Maeno, K. (2015) Quantitative Density Measurement of the Lateral Jet/Cross Flow Interaction Field by Colored-Grid Background Oriented Schlieren (CGBOS) Technique. Journal of Visualization, 18, 543-552. https://doi.org/10.1007/s12650-015-0297-7
[10]
Ota, M., Leopold, F., Noda, R. and Maeno, K. (2015) Improvement in Spatial Resolution of Background-Oriented Schlieren Technique by Introducing a Telecentric Optical System and Its Application to Supersonic Flow. Experiments in Fluids, 56, 1-10. https://doi.org/10.1007/s00348-015-1919-5
[11]
Leopold, F., Ota, M., Klatt, D. and Maeno, K. (2013) Reconstruction of the Unsteady Supersonic Flow around a Spike Using the Colored Background Oriented Schlieren Technique. Journal of Flow Control, Measurement & Visualization, 1, 69-76. https://doi.org/10.4236/jfcmv.2013.12009
[12]
Ardian, B.G., Burim, K. and Shigeru, O. (2013) Measurement Sensitivity and Resolution for Background Oriented Schlieren During Image Recording. Journal of Visualization, 16, 201-207. https://doi.org/10.1007/s12650-013-0170-5
[13]
Kak, A.C. and Slaney, M. (1988) Principle of Computerized Tomographic Imaging. IEEE Press, New York.