3. Operands#
3.1. Operand MODELE#
♦ MODELE = mo
Name of the model whose elements are the subject of thermal calculation.
3.2. Operand CHAM_MATER#
♦ CHAM_MATER = chmat
The name of the material field that is assigned on the model.
3.3. Keyword EXCIT#
♦ EXCIT =
Keyword factor used to define multiple loads. For each occurrence of the keyword factor, a constant time load is defined.
3.3.1. Operand CHARGE#
Charge-like concept produced by AFFE_CHAR_THER or by AFFE_CHAR_THER_F [U4.44.02].
Important notes:
For each occurrence of the keyword factor * EXCITles different concepts char used must be built on the same model mo.
In addition, the operator AFFE_CHAR_THER or AFFE_CHAR_THER_Fdoit must enter under the keyword factor * CONVECTIONun type concept cham_no_ DEPL_Rdéfinissant the speed of movement of the domain and produced by CREA_CHAMP.
Care must be taken to define boundary conditions consistent with the movement of the room (or the load, depending on the frame of reference chosen) and the assumption of stationarity:
If the solid is animated by a uniform translational movement at a constant speed, it is equivalent to considering the calculated temperature field:
like a photograph at a given moment,
or as a temporal succession of the temperature map in a fixed x-axis section, orthogonal to the direction of travel.
Thus, downstream in space (early in time), the boundary condition on the edge of the room must impose the temperature of the room before mobile charging arrives. Upstream in space (or late in time), zero heat flow (adiabaticity) guarantees the stationarity hypothesis.
3.4. Keyword ETAT_INIT#
◊ ETAT_INIT
Allows you to define the initial field from which the calculation in a moving coordinate system under the condition of stationarity is carried out.
3.4.1. Operand EVOL_THER#
Name of the evol_ther data structure from which the temperature field from which the solution to the problem is calculated is extracted.
3.4.2. Operand NUME_ORDRE#
/0 [DEFAUT]
Order number of the field to be extracted from this data structure.
Note:
For this type of calculation, there is no initial condition to define (it is defined with a boundary condition on one edge of the domain defined by the model). However, it is nevertheless possible to carry out the stationary calculation on the basis of a temperature field already calculated as a solution to the problem for only part of the load. This can be useful in cases where applying the full load makes convergence difficult. It is then possible to combine several resolutions with a loading that evolves progressively and take as the first iteration of a current calculation the solution of the previous calculation. Concretely, we then use the keyword ETAT_INIT to define the temperature field with which we want to initialize the current calculation.
3.5. Keyword CONVERGENCE#
◊ CONVERGENCE =
Allows you to define the values associated with the convergence criteria:
3.5.1. Operand CRIT_TEMP_RELA#
/test
The algorithm continues iterating as long as the relative variation of the iterate is greater than testr.
\({(\underset{i=\mathrm{1,}\mathrm{...},\mathrm{nb}\mathrm{ddl}}{\Sigma }{({T}_{i}^{n}-{T}_{i}^{n-1})}^{2})}^{1/2}/{(\underset{i=\mathrm{1,}\mathrm{...},\mathrm{nb}\mathrm{ddl}}{\Sigma }{({T}_{i}^{n})}^{2})}^{1/2}>\mathrm{testr}\)
where \({T}_{i}^{n}\) refers to the temperature value at node i for the nth iteration.
3.5.2. Operand CRIT_ENTH_RELA#
◊ CRIT_ENTH_RELA =/1.e-2
/testl
The algorithm continues iterating as long as the relative variation of the iterate is greater than testl.
\({(\underset{i=\mathrm{1,}\mathrm{...},N}{\Sigma }{({\beta }_{i}^{n}-{\beta }_{i}^{n-1})}^{2})}^{1/2}/{(\underset{i=\mathrm{1,}\mathrm{...},N}{\Sigma }{({\beta }_{i}^{n})}^{2})}^{1/2}>\mathrm{test1}\)
where \({\beta }_{i}^{n}\) designates the value of the enthalpy at the nth iteration at the 2nd Gauss point.
3.5.3. Operand ITER_GLOB_MAXI#
◊ ITER_GLOB_MAXI =/10
/Iterl
The algorithm continues external iterations as long as the number of external iterations is less than iterl.
3.6. Keyword SOLVEUR#
◊ SOLVEUR =
This factor keyword is optional: it allows you to choose another system resolution solver.
This operand is common to all global commands [U4.50.01].
3.7. Operand TITRE#
◊ TITRE = title
Title we want to give to the result stored in temp data structure of type evol_ther [U4.03.01].