caa a22 4500 606197761 CHVBK 20210128100931.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s00348-015-2081-9 doi (NATIONALLICENCE)springer-10.1007/s00348-015-2081-9 Focusing-schlieren visualization in a dual-mode scramjet [Elektronische Daten] [Toshinori Kouchi, Christopher Goyne, Robert Rockwell, James McDaniel] Schlieren imaging is particularly suited to measuring density gradients in compressible flowfields and can be used to capture shock waves and expansion fans, as well as the turbulent structures of mixing and wake flows. Conventional schlieren imaging, however, has difficulty clearly capturing such structures in long-duration supersonic combustion test facilities. This is because the severe flow temperatures locally change the refractive index of the window glass that is being used to provide optical access. On the other hand, focusing-schlieren imaging presents the potential of reduced sensitivity to thermal distortion of the windows and to clearly capture the flow structures even during a combustion test. This reduced sensitivity is due the technique's ability to achieve a narrow depth of focus. As part of this study, a focusing-schlieren system was developed with a depth of focus near ±5mm and was applied to a direct-connect, continuous-flow type, supersonic combustion test facility with a stagnation temperature near 1200K. The present system was used to successfully visualize the flowfield inside a dual-mode scramjet. The imaging system captured combustion-induced volumetric expansion of the fuel jet and an anchored bifurcated shock wave at the trailing edge of the ramp fuel injector. This is the first time successful focusing-schlieren measurements have been reported for a dual-mode scramjet. Springer-Verlag Berlin Heidelberg, 2015 Kouchi Toshinori Department of Mechanical and System Engineering, Okayama University, Tsushimanaka 3-1-1, Kita, 700-8530, Okayama, Okayama, Japan aut Goyne Christopher Department of Mechanical and Aerospace Engineering, University of Virginia, 570 Edgemont Rd., 22904-4248, Charlottesville, VA, USA aut Rockwell Robert Department of Mechanical and Aerospace Engineering, University of Virginia, 570 Edgemont Rd., 22904-4248, Charlottesville, VA, USA aut McDaniel James Department of Mechanical and Aerospace Engineering, University of Virginia, 570 Edgemont Rd., 22904-4248, Charlottesville, VA, USA aut Experiments in Fluids Springer Berlin Heidelberg 56/12(2015-12-01), 1-14 0723-4864 56:12<1 2015 56 348 https://doi.org/10.1007/s00348-015-2081-9 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00348-015-2081-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kouchi Toshinori Department of Mechanical and System Engineering, Okayama University, Tsushimanaka 3-1-1, Kita, 700-8530, Okayama, Okayama, Japan aut NATIONALLICENCE 700 1- Goyne Christopher Department of Mechanical and Aerospace Engineering, University of Virginia, 570 Edgemont Rd., 22904-4248, Charlottesville, VA, USA aut NATIONALLICENCE 700 1- Rockwell Robert Department of Mechanical and Aerospace Engineering, University of Virginia, 570 Edgemont Rd., 22904-4248, Charlottesville, VA, USA aut NATIONALLICENCE 700 1- McDaniel James Department of Mechanical and Aerospace Engineering, University of Virginia, 570 Edgemont Rd., 22904-4248, Charlottesville, VA, USA aut NATIONALLICENCE 773 0- Experiments in Fluids Springer Berlin Heidelberg 56/12(2015-12-01), 1-14 0723-4864 56:12<1 2015 56 348