Ali Yari - Master of Science of Mechanical Engineering , North Research Institute
Moosa Heidarnataj Baee - Master of Science of Mechanical Engineering , North Research Institute
Ebrahim Alizadeh - PHD of Mechanical Engineering , North Research Institute
Hamid Gholami baee - Master of Science of Airospace Engineering , North Research Institute ,North Research Institute

Hydrodynamic coefficients strongly affect the dynamic performance of an unmanned underwater vehicle. Computational Fluid Dynamic (CFD) based on Reynolds Averaged Navier–Stokesequation is used for determining the transverse hydrodynamic damping force coefficients that are needed in the maneuverability study of submarine vehicles. Computations are performed for a geometrical shape representing typical UUVs presently in use at typical Reynolds of Unmannedunderwater vehicles motion (from 2.5×105 to 1×106) by varying pitch angles (from 0 to 25 Deg.).The analysis was used to study variation of axial, normal force coefficients with Reynolds number (Re) and angle of attack.

CFD, hydrodynamic coefficient, unmanned underwater vehicles