Investigation of flow in colliding underexpanded coaxial jets

The qualitative patterns and characteristic geometry of colliding underexpanded coaxial jets over a wide range of nozzle-discharge parameters are described. Analysis of schlieren photographs led to description of the possible collision patterns and the domain of their existence. A single self-similarity parameter for the collision of jets with their first barrels, and also empirical formulas relating the location of shock waves and the interface to the flow variables were derived. A method for determining the location of centered shocks and interface in colliding jets, employing empirical formulas and the condition of equality of stagnation pressures on the interface, are suggested. The method is illustrated by computational examples.