[cfd seeker]

hi all, I am new fluent user and i m doing CFD analysis of a general stepped missile body(diameter is different at different locations) in fluent. My aim is to find the CL,CD,CM at M=2 and AOA ranging from 2 to 10 degrees. I am using coupled implicit solver with steady state. I have made the mesh in Gambit and it has 2.6 million cells. Currently i am doing a run at 2 deg AOA and it took 14,000 iterations to converge(not fully converged,still the cofficients has some fluctations). My mesh is very large so my computer is taking 1 min/iteration. I have kept the courant no to 1 because solution diverges as i increase it beyond 1. So my solution is converging very slowly and taking a lot of time. I have heard that there are some MULTIGRID settings which aid in fastening convergence but i am totally illetrate in their knowledge. Can somebody please help me in these MULTIGRID settings or suggest something else which helps me in faster convergence?????
Any suggestions will be welcomed as my solution is taking alot of time and i have limited time to perform analysis at other AOA's.
Thanx in advance