Simulation of the dynamic retrieval process of a towed target system under towing airplane’s wake and atmospheric turbulence

Abstract

This paper studies the dynamic retrieval process of a towed target system under perturbation by simulating the reel-in operation under the towing airplane’s wake and atmospheric turbulence. To settle the computational problem of cable tension, the constant-length method is proposed to transform this variable-mass problem into a constant-length problem based on a mass-spring model that discretizes the cable. A three-dimensional atmospheric turbulence field is built using a recursive function to model the complex perturbation field along the cable. A horseshoe vortex model is adopted to simulate the towing airplane’s wake. Simulation analysis shows that both the reel-in speed and turbulence significantly affect the retrieval deviation, whereas the airplane’s wake has little influence. The reel-in speed should be chosen in concert with the turbulence intensity to achieve a high retrieval success rate. Moreover, a higher reel-in speed is preferred to maintain cable strain and smoothen the process when the retrieval tolerance is satisfied.