# Node ID Ordering in Mesh

Member

Hello all,

I have a simple cuboid model, which is separated in two parts. The length of edge A is constant. The length of edge B is a parameter (changing from 3.0mm to 3.2 mm). In order to keep the total number of nodes in the mesh always the same, I applied the 'Sizing' function on two edges (See Figure). 'Number of divisions' of edge A is set to be 10 and edge B is divided into 30 divisions.

I found that with different length of edge B, although the total number of nodes in the mesh is controlled as the same, but the node ID ordering in the mesh is different. How can I control the node ID ordering in the mesh and make them the same?

Chengdong

• Member

@Chengdong Why do you care what the node ID is?

• Member

Hi peteroznewman,

This model is simulated by using the static thermal analysis system. The system matrices of the model are extracted out of ANSYS when the length of edge B is 3.0 mm and 3.2 mm, respectively. The system matrices will be different depending on the geometrical parameter in this model. For example, the thermal conductivity matrix is K(L), which is dependent on the length of edge B.

Now I want to get the simulation result of this model when the length of edge B is set as 3.1mm. Instead of changing this parameter in ANSYS and do the simulation, I want to construct an interpolated system by interpolating the system matrices of these two local models, in which L=3.0 mm and L=3.2mm,respectively. For example, the new thermal conductivity matrix is obtained through the equation: K(L=3.1mm)=0.5*K(L=3.0 mm)+0.5*K(L=3.2 mm), where 0.5 is the weight. Then I could solve the newly interpolated system in other software to get the simulation result of the model with parameter L=3.1 mm.

In my understanding, the node ID ordering will decide the row ordering in the matrices. Through the tests, it is found if the row ordering can't be kept the same in both local system matrices, then the result from the interpolated system will not be good. That's why I need to control the node ID ordering.