Hi...I am trying to simulate the motion of a water(bottle) rocket caused by its thrust(ejecting water&air) using explicit 2 phase VOF ,Dynamic  Mesh and 6 DOF UDF.Without 6 DOF(static simulation), everything runs smoothly but when 6 DOF is checked,pressure inside bottle becomes very high and both bottle and water appears static and finally AMG solver diverges.When I use air only everything also runs smoothly as expected(bottle shoots up)..What could the problem be !!!..any help would be appreciated.initial pressureinitial volume fraction