Reduced-Order Model of Jet Interaction Force on Basic Finner

This study proposes an engineering level approximation to predict the jet interaction force as a function of freestream conditions, body geometry, and jet parameters through simplifications of the complex aerodynamic system generated by a jet and crossflow interaction to predict the resultant forces. The reduced-order model (ROM) is split into two components, with each component describing a distinct phenomenon: the jet interaction with the body and the interaction between the shock generated by the jet and the fin. It has been shown that the jet and body interaction force is self-similar in Mach number and pressure ratio, and an artificial neural network is used to compute the forces along the body. Computing the force generated by the bow shock introduced by the jet impinging upon the fin is accomplished by using analytical relations for the blockage caused by the jet, computing the resulting intersection between the fin and shock, and finally projecting the pressure change across the shock onto the fin. The two ROMs are simply combined through addition to attain the overall jet interaction force. With the models combined, the average error when compared to a Reynolds-averaged Navier–Stokes solution was approximately 20%, which can be directly attributed to assumptions made creating the model, particularly the jet wake and fin interaction being ignored. It was found that this model is a viable alternative to computational fluid dynamics by providing an adequate approximation for preliminary design with many orders of magnitude less compute time.