Experimental Investigation into the Vectoring Performance of Asymmetric Bypass Dual Throat Nozzles

Bypass dual throat nozzles were first proposed in the 1990s as a means to enable more effective and efficient control of combat aircraft, but real-world implementation has not yet been demonstrated. In an attempt to mitigate this gap, this study provides an extensive experimental investigation through conducting simultaneous pressure measurements and schlieren flow visualization to inform the design of this concept. Symmetric double-sided, single-sided, and asymmetric double-sided air injection cases were all tested. For symmetric injection, while vectoring is not targeted, the ability to move the aerodynamic throat location is demonstrated. When vectoring is considered, it is shown that the highest vectoring efficiency, assessed in terms of vectoring angle per injection slot size, is achieved via single-sided injection while using the smallest injection slot to throat diameter ratio realized in this study. Finally, for asymmetric double-sided injection, it is shown that for the same net injection, the loss in vectoring efficiency can exceed 29% compared to single-sided injection.