On steady and pulsed low-blowing-ratio transverse jets
Document Type
Article
Publication Date
1-10-2013
Abstract
The present experimental and numerical study focuses on the vortical structures encountered in steady and pulsed low-blowing-ratio transverse jets ( 0. 150≤ BR≤ 4. 2), a configuration hardly discussed in the literature. Under unforced conditions at low blowing ratio, a stable leading-edge shear-layer rollup is identified inside the jet pipe. As the blowing ratio is increased, the destabilization and evolution of this structure sheds light on the formation mechanisms of the well-known transverse jet vortical system. A discussion on the nature of the counter-rotating vortex pair in low-blowing-ratio transverse jets is also provided. Under forced conditions, the experimental observations support and extend numerical results of previous fully modulated jet studies. Large-eddy simulation results provide scaling parameters for the classification of starting vortices for partly modulated jets, as well as information on their three-dimensional dynamics. The counter-rotating vortex pair initiation is observed and detailed in both Mie scattering visualizations and simulations. The observations support a mechanism based on stretching of the starting vortical structures because of inviscid induction and partial leapfrogging. Two modes of cross-flow ingestion inside the jet pipe are described as the pulsed jet cycles from high to low values of blowing ratio. © 2013 Cambridge University Press.
Publication Source (Journal or Book title)
Journal of Fluid Mechanics
First Page
393
Last Page
433
Recommended Citation
Bidan, G., & Nikitopoulos, D. (2013). On steady and pulsed low-blowing-ratio transverse jets. Journal of Fluid Mechanics, 714, 393-433. https://doi.org/10.1017/jfm.2012.482