### 6.2.3. Rotation Force

In a rotating frame of reference, the rotation term is an intrinsic part of the acceleration and is the sum of Coriolis and centripetal forces:

| (6–18)

As described elsewhere (see Pressure Gradient Force and Virtual or Added Mass Force), the implemented rotation term also contains contributions from the pressure gradient and the virtual mass force due to the domain rotation, which leads to the following final contribution of the rotation term to the right hand side of Equation 6–7.

| (6–19)

Using the substitutions:

Equation 6–19 can be written as:

| (6–20)

where

- if neither pressure gradient nor virtual mass force is taken into account

- if only virtual mass force is taken into account

- if only pressure gradient force is taken into account

- if pressure gradient and virtual mass forces are taken into account

The rotation force has no contribution to the particle momentum source into the continuous phase.

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