POLYDATA - POLYFLOW : how to define a PMAT on heat flux boundary condition?
The heat flux boundary condition q is described as q = q0 + alpha.(T-Talpha) + sigma (T^4). In other words, it consists successively of a constant part, a convective part and a radiative part. In the internal data structure, the constant quantity q0 is defined as a field, while alpha and Talpha are real parameters. PMAT features cannot be applied on fields, and thus a PMAT cannot be defined on q0. Based on this, how can one define a PMAT on the heat flux?
Let us assume that the user wants to define a PMAT feature on a constant heat flux q0. The quantity q0 can be defined as the product alpha.(T-Talpha). This can be achieved as follows:
- Select alpha = q0; a PMAT will be defined beyond;
- Select Talpha = 1, and define a PMAT on Talpha;
- Select the polynomial function for the PMAT on Talpha, with a polynomial dependence on T (temperature), and choose a=-1, b=1, c=d=0; by doing so, the resulting (convective) heat flux is given by alpha.(T-(T-1)) = alpha;
- Eventually, another PMAT can be defined on alpha, depending on the case to be simulated.