Spinning Projectile
 

Hi. I have to predict the aerodynamic coefficients of a spinning projectile. I am using Fluent 15 solver. I generated the mesh of 1.4 million elements. I am performing the steady simulations using double precision, density based, explicit solver. The viscous model is Transition 4 Equation SST. I have to perform the simulations between 0.6 to 2.5 Mach number at different angles of attack. My problem is that the solution does not converge for lower Mach numbers even after 4000 iterations. Can any one please help me?