This paper presents an experimental study of reacting hydrogen jet in crossflow (JIC). High-speed shadowgraph images are used to capture flame dynamics. The flame jet is first compared with non-reacting helium JIC. It is observed that the vortical structures that are present densely in helium jets are significantly reduced in the hydrogen jet. Furthermore, unforced jets with various velocity ratios are studied. It is noted that jet penetration increases with the jet to crossflow momentum ratio. Proper orthogonal decomposition analysis is used to characterize the spatiotemporal behavior of the reacting jet. Furthermore, the jet is acoustically forced with a range of frequencies and it is observed that the flame response is more prominent for higher forcing frequencies. This aspect is further explored using Kelvin–Helmholtz instability analysis. It is noticed that a higher velocity ratio produces stronger interaction with the crossflow, which dampens the effect of forcing. A novel interface tracking method is used to characterize the shear layer instability from shadowgraphy images. This is perhaps the first attempt where high-speed shadowgraphy images are used to obtain quantitative information on the shear layer, which also compares well with theoretical analysis. This paper also presents the first experimental study of forced hydrogen flame jet in crossflow configuration.
Kumar et al. (2026) studied this question.