How to apply Robin BCs?

[K-Komal-98]

I am modeling a battery problem. There are 3 blocks : anode, electrolyte and cathode. There are also robin BCs in the problem like d^y_1/dx + y_1^2 = g. Is their any block corresponding to this kind of BC?

[hugary1995]

Use a MatNeumannBC in conjunction with a ParsedMaterial. Below is an example of imposing heat convection BC:

[BCs]
  [hconv]
    type = ADMatNeumannBC
    variable = T
    boundary = 'insul_od insul_top_bot'
    value = -1
    boundary_material = qconv
  []
[]

[Materials]
  [qconv]
    type = ADParsedMaterial
    property_name = qconv
    expression = 'htc*(T-T_inf)'
    coupled_variables = 'T'
    constant_names = 'htc T_inf'
    constant_expressions = '${htc} ${T_inf}'
    boundary = 'insul_od insul_top_bot'
  []
[]