how to consider gravity in CFX

shrimp

For a pump simulation, the roation axis is set as Z Dirn. As the medium is water, I think gravity should be considered. But when I set "Buoyancy" -> Gravity Y Dirn: -9.8 m s^-2, Gravity X,Z Dirn: 0. I got a error message shown as below. I think it is werid. Because according to the momentum equation, gravity can be added even it is not aligned with rotation axis. Am I right? and if so, how can I add gravity in steady-state?

| ERROR #001100279 has occurred in subroutine ErrAction. | | Message: This simulation involves a gravity vector which is not aligned with the rotation axis. This is valid only if the simulation type is transient, but it is currently set to steady-state. Please change the setup accordingly