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Hi everyone,

In my analysis, I get the following error message:

Error:
Failed to find consistent initial values.
Power_of_negative
Function: power
Failed_to_evaluate_variable
Variable: i0, Defined_as: (((k_neg*((c1max_pos-c1s_pos)^aA_pos))*(c1s_pos^aC_pos))*(c2^aA_pos))
Failed_to_evaluate_variable
Variable: i_loc, Defined_as: ((exp((((Far*aA_pos)*eta)/(Rg*T)))-exp(((((-aC_pos)*Far)*eta)/(Rg*T))))*i0)
Failed_to_evaluate_expression
Expression: diff(((-K1eff*phi1x*test(phi1x)/L_pos-K1eff*phi1y*test(phi1y)/L_pos-i_loc*Sa_pos*L_pos*test(phi1))-(0))*(dvol),{test@2})
Last time step is not converged.

It seems that in the expression of the variable i0, the terms of which power is wanted is negative, so its power is a complex number. For example, in (c2^aA_pos) c2 is negative (by the way 'aA_pos' is constant and it is 0.5, therefore it is a squareroot operation). As I understood, COMSOL cannot calculate i0 (and so that i_loc, since it includes i0), because a squareroot of a negative number is a complex number. However, I have checked all the values of which squareroot is wanted and all of them are positive.

Anyone have an idea for this error?

Thanks in advance.

Regards,
Özen