Shallow water experiments are predestined for fast and inexpensive experimental examination of two-dimensional (2D) flow phenomena. In this study, the shallow water analogy is used for the verification of a previous numerical analysis of an aerodynamically thrust-vectored aerospike nozzle. Experiments in a shallow water channel were conducted, using a model of an isentropic spike with a 25 percent truncation and two secondary injection sites. A comparison of the flow phenomena, e. g., shock patterns, shows a wide correspondence of experimental and simulation results, thus verifying the simulation approach and encouraging to continue its improvement. Furthermore, it can be shown that secondary fluid injection is a promising method for active thrust vectoring on aerospike thrusters and gives an objective for future applications.

The generally adopted flow model inside a swirl injector, widely used injection concept for propulsive applications, relies upon the hypothesis of ideal flow neglecting the fluid viscosity effects. This model showed significant prediction errors with relatively high viscosity propellants, often leading to the need of an experimental characterization of the injection elements. In this paper, an analytical approach is presented, which includes the effects of viscous diffusion on the injector performance leading to a close form flow solution. The built model is thus experimentally validated testing a liquid oxygen (LOx) and an ethanol injector: the good agreement between the model and the experimental results leads to the construction of the injectors operational maps describing the injector behavior even in the presence of viscous effects.