Fluidic Control of a 155 Millimeter Spin-Stabilized Projectile Using Coanda Effect

Abstract

The present paper aims at investigating numerically the control of a 155 mm spin-stabilized projectile using the Coanda effect. The flight Mach number ranges from to . A tangentially blowing jet exits over a convex surface at the base of the projectile and creates flow asymmetry, which generates significant aerodynamic loads. First, Reynolds-averaged Navier–Stokes simulations are performed without projectile rotation. The jet extends 18 deg azimuthally, and numerous continuous blowing conditions are assessed. The variation of the normal force coefficient with respect to the jet momentum coefficient is presented for different freestream Mach numbers. The efficiency loss of the Coanda effect with supersonic jets is specifically discussed. Additionally, comparisons between overexpanded, adapted, and underexpanded supersonic jets are presented. In the second part, unsteady Reynolds-averaged Navier–Stokes simulations, accounting for a 400 Hz projectile rotation, are performed. Both continuous and periodic blowing are assessed. A pulsed jet is used in phase with the rotation to always act in a 90 deg sector centered in the lift plane. The resulting normal force benefits are more important than in the nonspinning case, and spin-averaged values lead to a nonzero normal force increment. Then, four pulsed jets equally distributed along the circumference of the projectile are simulated to further improve the control efficiency. The jet separation process is also investigated to determine the influence of the jet on the base pressure distribution.