Dear all

In Comsol 6.2, There are two ways to acquire previous variable value in transient analysis.

The one way is adopting previous solution operator.

The other way is adopting state variable.

Now, Taking Heat transfer for example: variable is T, I set a new variable Tb to record the previous value of T.

Here, T_initial value = 293K and Tb_initial value = 0K

I tried both of them and plot the figure to see if the previous variable value Tb match T value.

Theoretically:

When T(t=0)=293K, T(t=1)=297K, T(t=2)=310K

The Tb should be Tb(t=0)=0K, Tb(t=1)=T(t=0), Tb(t=2)=T(t=1) etc.

However, there are some error between Tb(t=1)=T(t=0), Tb(t=2)=T(t=1)...

Does anyone meet this question? I would like to know is there anyway to verify this issues?