difference between frame motion and mesh motion in fluent
 

Dear friends,
There is an option provided in fluent in cell zone condition of frame motion and mesh motion, i want to know the difference between both the option.
Natural convection for differentially side heated cavity filled with fluid and rotating with a high speed such that centrifugal force must act inside the cavity.
Is there any other option can be given for the same.

Thanks in advance!!! :)

Hello jaiswal,
I suggest reading Fluent Guides about Single/Multiple Reference Frame (and Mixing Plane, as well) and Sliding Mesh Model: the first is activated with Frame Motion, the second with Mesh motion.
Surely, Sliding Mesh model is more complicated but more reliable in some situations.

Regards

If there is no interface in the domain, is it advisable to use mesh motion along with frame motion? Because if I am using only frame motion then there occurs no motion in animation. While using a frame with mesh motion ...or only mesh motion, there is the motion as I can see in animation. I find no relative literature which relates mesh or frame motion without interface.

Mesh and Frame Motion
 

In mesh motion, Fluent makes the domain move as per the user specification. Since there is motion of the mesh, it is a must to have a non-conformal interface at the junction of cell zones that have relative motion. Non-conformal mesh does not imply that mesh has to be different; it can be exactly same mesh or different mesh on both sides, however, there has to be individual boundaries belonging to each cell zone at the junction. Mesh motion is meant for simulations where user is interested in predicting transfer of flow or some other field across the interface without any kind of averaging, such as, transfer of eddies or shock waves. It is more accurate, however, can only be run as transient. Mesh motion has only one reference frame, the inertial one.

Frame motion based approaches do not involve motion of the cell zones. Instead, forces are calculated due to the motion and added as momentum source terms to the cell zone. The motion is given to the reference frame so that the cell zones have zero relative motion with respect to its own reference frame leading to same conservation equations as those without any motion with force terms added. Frame motion simulations can be steady-state or transient (if speed or direction is a function of time). SRF/MRF are same, except that SRF has only one cell zone and one reference frame attached to that cell zone. MRF has more than one cell zone and each has its own reference frame. Some of these may be moving. Frozen rotor approach can also transfer the fields across cell zone boundaries, almost unaltered, just like mesh motion. But mixing plane does the averaging of the fields before transfer. Therefore, no transient phenomenon can transfer across mixing plane. Everything gets averaged out.

Thanks...great explanation

Mesh motion or frame motion for CHT
 

Hello all,

I am trying to simulate conjugate heat transfer in a gas turbine blade. I have both fluid and solid domains. I am confused regarding the following aspects:

1. What would be the better way to implement the rotation of the turbine: mesh motion or frame motion?
2. To which domain/ mesh should I apply motion, fluid/ solid/ both?

Thank you!