Model of the Trajectory of an Inclined Jet in Incompressible Crossflow

Abstract

A simple model of the flowfield induced by an inclined jet into an incompressible crossflow is proposed. In general, such a jet generates an asymmetric pair of vortices, with a larger one farther from the wall. The model accounts for the influence of the jet pitch angle (with respect to the wall), skew angle (with respect to the freestream direction), and velocity ratio (the jet velocity to the freestream velocity) on the jet trajectory in the transverse plane in the far field. From the model, the increase of the jet penetration and the circulation of the large vortex in the transverse plane to the downstream distance obeys to the same one-third law in the case of normal transverse jet. Data from the literature are normalized and compared to the model. Although there is considerable scatter, the normalized data are generally in accord with the predictions of the model. However, for low velocity ratios when skew angle is near 90 deg, the effect of jet entrainment, and the effect of the horseshoe and wake vortices, may create a low-pressure region on the wall and hence alter the jet trajectory and influence the circulation.