The shape of the axisymmetric compressible subsonic impinging jets

This work is intended as an attempt to investigate the geometric shape of the free streamline for a threedimensional axisymmetric compressible subsonic impinging jet, which ejects from a semi-infinitely long nozzle and impacts onto a ground. More precisely, based on the existence theory in the previous work [13], we will first show that the differential pressure pdiff between the upstream and downstream is monotonic and continuous with respect to the incoming mass flux M0. The other main purpose of this paper is to prove the convexity of the free streamline, provided that the ground is assumed to be concave to the fluid. In addition, under the corresponding assumptions regarding the nozzle wall and ground, we also show the monotonicity of the free boundary and the negativity of the axial velocity. (c) 2025 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.