Computational Fluid Dynamics Study for Drag Reduction of an Airborne Surveillance Gimbal

Abstract

This study describes the drag minimization of an existing gimbal assembly mounted to an airplane, scanning a sight for surveillance purposes. This has been numerically investigated using the Computational Fluid Dynamics method supported by Fluent 19.2 software, solving Reynolds-Averaged Navier Stokes. For the existing surveillance system, the given flight operational conditions were analyzed based on the International Standard Atmosphere where the flow obtained is incompressible turbulent flow. To start the simulations, study on simple 2D and 3D sphere simulations were conducted at two Reynolds number of 1×106and 1.564×106 using two different turbulence models, the k-ω SST and k-ε realizable. Drag, lift, and separation angle data were computed and compared to validate the code. The simulated values were in excellent agreement with results found both experimentally and computationally. Based on the flow simulation setup of the sphere, the existing gimbal was simulated for Reynolds number of 1.564×106 comparing both turbulence models k-ω SST and k-ε realizable. A large zone of vorticity, low-pressure wake, separation, and vortex shedding were observed introducing colossal drag. Two solutions were suggested in this study, which are changing the existing gimbal orientation and optimizing gimbal geometry. The simulation results described in this study have illustrated the capability of both turbulence models. The results obtained agreed well when compared computationally and experimentally. Improvements of almost 60% were achieved by the two suggested solutions where the optimized gimbal shows a higher improvement percentage.

Date of Award	May 2019
Original language	American English