Repeating Dymamic Mesh

arthur106 · December 4, 2016, 23:31

I'm running a 3d transient simulation on two gears that are meshed together with a very small gap between them. Each time step is solved fairly quickly, but remeshing between each time step takes forever. In order to speed up the simulation, I was wondering if it would be possible to create the meshes for each time step before beginning the simulation.

The theory of this would work like this: My gears have 23 teeth each, and with my given time step size, it will take "n" time steps to complete a revolution of both gears. Before running the simulation, I could create 23/n meshes, each corresponding to a different time step. At each new time step, Fluent loads the next mesh in the series. When it gets to the end, the gears are in the same position due to the axisymmetric condition and fluent loops back to the first mesh and then repeats.

I'm new to Fluent and haven't found my answer in the theory guide or user guide. Can someone point me in the right direction to get started?

arthur106 · December 5, 2016, 14:00

After a good night's sleep, I realize my explanation was entirely wrong. Let me try again.

For gears having "n" teeth, a time-step would be chosen such that it would take exactly m*n time-steps to complete a full revolution (where "m" is an integer). Due to axial symmetry, the gears would essentially be in the same position after m time-steps. Thus m number of meshes could be created and used for the first m time-steps. On time-step m+1, the mesh from time-step 1 could be used because of the axial symmetry. On time-step m+2, the mesh from time-step 2 would be reused ... and so on ... time-step m+x would use the same mesh as time-step x.

December 4, 2016, 23:31	Repeating Dymamic Mesh	#1
arthur106 New Member Jacob Join Date: Sep 2016 Posts: 10 Rep Power: 9	I'm running a 3d transient simulation on two gears that are meshed together with a very small gap between them. Each time step is solved fairly quickly, but remeshing between each time step takes forever. In order to speed up the simulation, I was wondering if it would be possible to create the meshes for each time step before beginning the simulation. The theory of this would work like this: My gears have 23 teeth each, and with my given time step size, it will take "n" time steps to complete a revolution of both gears. Before running the simulation, I could create 23/n meshes, each corresponding to a different time step. At each new time step, Fluent loads the next mesh in the series. When it gets to the end, the gears are in the same position due to the axisymmetric condition and fluent loops back to the first mesh and then repeats. I'm new to Fluent and haven't found my answer in the theory guide or user guide. Can someone point me in the right direction to get started?

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December 5, 2016, 14:00		#2
arthur106 New Member Jacob Join Date: Sep 2016 Posts: 10 Rep Power: 9	After a good night's sleep, I realize my explanation was entirely wrong. Let me try again. For gears having "n" teeth, a time-step would be chosen such that it would take exactly *mn** time-steps to complete a full revolution (where "m" is an integer). Due to axial symmetry, the gears would essentially be in the same position after m time-steps. Thus m number of meshes could be created and used for the first m time-steps. On time-step m+1, the mesh from time-step 1 could be used because of the axial symmetry. On time-step m+2, the mesh from time-step 2 would be reused ... and so on ... time-step m+x would use the same mesh as time-step x.