Experimental investigation of a jet impinging on a ground plane in crossflow

J. M. Cimbala, D. R. Stinebring, A. L. Treaster, M. L. Billet, M. Walters

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

An experimental investigation has been conducted in a wind tunnel to model the impingement of high-velocity jet exhaust flow on the ground, as encountered by V/STOL aircraft. A constant jet velocity was maintained while varying the wind tunnel crossflow velocity, upstream boundary-layer thickness, and height from the ground to the jet exit plane. The radial wall jet, when interacting with the crossflow, forms an oscillating horseshoe-shaped separation bubble, commonly referred to in the literature as a ground vortex. The streamwise distance of the separation point from the jet impingement point is documented here as a function of the flow parameters and geometry. Flow visualization of the flowfield and two-component laser Doppler velocimeter measurements taken through the separation bubble indicate that the separation bubble is highly unsteady and nonsymmetric. This unsteadiness may be related to shear-layer vortices shed from the lip of the jet. Thickening of the upstream boundary layer on the ground plane caused the wall jet to penetrate further upstream. The addition of a large plate flush-mounted to the jet exit caused the ground vortex to move downstream and also decreased the size of the ground vortex.

Original languageEnglish (US)
Pages (from-to)923-931
Number of pages9
JournalJournal of Aircraft
Volume25
Issue number10
DOIs
StatePublished - Oct 1988

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering

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    Cimbala, J. M., Stinebring, D. R., Treaster, A. L., Billet, M. L., & Walters, M. (1988). Experimental investigation of a jet impinging on a ground plane in crossflow. Journal of Aircraft, 25(10), 923-931. https://doi.org/10.2514/3.45681