Shock Waves (2007) 16:275–285 DOI 10.1007/s00193-006-0068-4 ORIGINAL ARTICLE Heat flux measurement over a cone in a shock tube flow T. Kuribayashi · K. Ohtani · K. Takayama · V. Menezes · M. Sun · T. Saito Received: 22 June 2006 / Accepted: 12 November 2006 / Published online: 16 February 2007 © Springer-Verlag 2007 Abstract This paper is the part 2 of our previous thin film heat transfer measurements. In the first report we measured time variations of heat flux over a cylinder placed in a shock tube flow and compared experimen- tal results with CFD results, Saito et al. (Shock Waves 14:327–333, 2004). We report a result of heat trans- fer measurements over an 86 ◦ apex angle cone surface impinged by a Ms = 2.38 shock wave in air with distrib- uted thin film transfer gauges along cone surface and its comparison with results of numerical simulations. We performed double exposure holographic interfer- ometric observation, and also from the heat transfer measurement and numerical simulation, confirmed the presence of delayed transition from regular to Mach reflection over the cone. The numerical estimation of delayed transition distance from the apex agreed very well with experimental one. Keywords Delayed transition · Heat transfer measurement · Holographic interferometry · Conical flow · Numerical simulation PACS 47.40.Nm · 42.40.Kw Communicated by E. Timofeev. T. Kuribayashi · K. Ohtani · K. Takayama (B ) · V. Menezes · M. Sun Interdisciplinary Shock Wave Research Laboratory, Institute of Fluid Science, Tohoku University, 2-1-1, Katahira, Aoba, Sendai 980-8577, Japan e-mail: takayama@rainbow.ifs.tohoku.ac.jp T. Saito Department of Mechanical Systems Engineering, Muroran Institute of Technology, 27-1, Mizumoto, Muroran 050-8585, Japan 1 Introduction We have been interested in quantitative measurements of heat transfer over bodies exposed to high-tempera- tures behind strong shock waves which were producible in a detonation-driven diaphragm-less shock tube. Since in conventional shock tube flows in which shock waves are generated by rupturing diaphragms, fragments out of ruptured diaphragms may hit or scratch thin film heat transfer gauge surfaces, the repeated use of the gauges no longer produced reliable data. Fay and Riddell [1] studied the stagnation heat trans- fer in dissociated air. Rose and Stark [2] performed hypervelocity shock tube experiments by using thin film heat flux gauges, and verified the formula [1] for hyper- sonic stagnation point heat transfer. These are typical results obtained in early shock tube research. How- ever, heat transfer measurements in shock tube or shock tunnel flows still belong to unaccomplished technology. Recently, Kuchiishi et al. [3] mentioned in their free piston shock tunnel heat flux measurement, that the noises superimposed on heat flux signals were presum- ably attributable to the impingement of diaphragm frag- ments on the heat flux gauge surface and that the heat flux data acquisition was terminated because of fatal fragment impingements on its surface. Aso et al. [4] used thin film heat transfer gauges on a movable wedge in a conventional shock tube, and reported that the first output signal corresponded to the arrival of an incident shock wave and the second output signal to the slip line sweeping on the gauge sur- face. Fragments shuttering from ruptured diaphragms deteriorated their reliable data acquisition. Having refurbished a 100 mm × 180 mm shock tube to diaphragm-less operation [5], we plan to experimentally