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Defining non-constant Neumann Boundary Conditon

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Andrew Ferguson
Andrew Ferguson on 21 Jan 2020
Answered: Ravi Kumar on 22 Jan 2020
I am a little unsure if I am using the correct syntax for defining my non-constant neumann boundary condition for a time-dependent PDE.
specifyCoefficients(model,'Face',2,'m',0,'d',1,'c',Da,'a',0,'f',0);
specifyCoefficients(model,'Face',3,'m',0,'d',1,'c',Dg,'a',0,'f',0);
applyBoundaryCondition(model,'neumann','Edge',8,'q',0,'g',@gcoeff2);
function f = gcoeff2(~,state)
rhog = 1250;
rhoa = 1.150;
Da = 2.82*10^-4;
f = (Da.*rhoa./rhog).*(state.ux+state.uy);
end
Esentially I have two areas occupied by different substances, which share a common edge, Edge 8. I want to apply the equal flux boundary condition at edge 8 such that
Is the code for my function correct? Is it necessary for me to add in locations even though the gradient is defined by "state.ux" and "state.uy"? Also, since it is a time dependent PDE do I need to multiply everything by state.time?

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Answers (1)

Ravi Kumar
Ravi Kumar on 22 Jan 2020
You do not need to model the interface BC explicitly. This condition should be automatically satisfied in the solution.
Regards,
Ravi

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