Initial conditions in Transient thermal: overview
Transient application: reminder
A transient application is a physical application characterized by:
- properties that vary in function of time: variable sources, variable material characteristics…
- a time equation (differential equation of the 1^{st} order) : d/dt ≠ 0 (transient regime or variable regime).
The resolution consists of a sequence of resolutions in time. The solutions are not independent from each other: each solution is linked to the previous one by the temporal equation.
General case
In the most general case, the state variable (the temperature) is initialized at a predefined initial value T_{init} (pour t = 0). The1^{st} time step (t = t_{1}) corresponds to the first Flux solving, as shown in the table below.Initial instant | 1 st time step | … | |
---|---|---|---|
Flux Solver | t = 0 | t = t_{1} | |
Temperature | T_{0} = T_{init} | T_{1} = T_{computed} |
Note: The value of the initial temperature is defined at the level of the solving
options.
Particular case
It is possible to start a new transient thermal computation by using as initial state the result of a Steady State Thermal application or of a Transient Thermal application.
This permits, for instance, to resume a computation after the modification of the values of a physical quantity (convection coefficient...)