• High Enthalpy Hypervelocity Experiments: Bridging the Scales

Complex, nonlinear interactions between molecular processes (thermal transitions, chemical reactions) and gas dynamics are a hallmark of hypervelocity flight conditions such as those encountered by man-made or naturally-occurring objects during planetary entry. This presentation discusses our recent work in hypervelocity flows where the response of the global flow features (sush as schock configurations, and thermal and aerodynamic surface loading) are sensitive to the thermochemical state of the gas. These experiments are carried out in two impulse facilities at Caltech: the T5 free piston shock tunnel and the Hypervelocity Expansion Tube. Our diagnostic tools include direct spectroscopic measurements of naturally-ocuring (post-shock) dissociated species and vibrational temperatures, overlaid with flow structure visualizations, to dissect the interplay between real gas effects and flow processes, as well as high speed imaging of the gas dynamic features. Using these tools, we examine the coupled interaction of energy exchange across a range of scales from macroscopic to molecuar in high stagnation enthalpy, hypersonic flows. 

The Wu Lectur in Aerospace is given to honor and thank Caltech alumni Susan and James Wu for sponsoring the GALCIT Distinguihed Professo Lecture series that began in 2010 and has had a significant impact on all who attended.