solvepde function MATLAB "c" term identification

Hi everyone ! I have a question regarding the solvepde function in matlab.

In particular, I have problems in indentifying the "c" term. My equation has inside a term like this:

The variables are V and p (I have a system of equations).

I have difficulties in separating this term and understand which term is "c".

Thank you in advice !

Bests,

Ciro

Answer 1

[Torsten]

https://uk.mathworks.com/help/pde/ug/c-coefficient-for-systems-for-specifycoefficients.html

Chapter

Definition of the c Tensor Elements

[CIRO]

Thank you for your aswer !

I have also another question.

One of my boundary condition has inside a time-dependent term that is solved by an ODE that depends on the values of the dependent variables calculated at the end of the domain.

How could I implement this situation in solvepde (if it is possible)?

Thanks again !

Bests,

Ciro

[CIRO]

I have also another question sorry.

Is it possible to insert in the coefficient a the second derivatives of the dependent variables? (considering that I am trying to solve a system of three equations, I have in one equation a term )

Thanks again.

[Torsten]

One of my boundary condition has inside a time-dependent term that is solved by an ODE that depends on the values of the dependent variables calculated at the end of the domain.

How could I implement this situation in solvepde (if it is possible)?

I'd try to solve the problem by calling "solvepde" in a loop where you advance the solution by a time step deltat. Use the results at the end of the domain to advance the solution of the ODE also by this time step deltat and work with this value in the next call to "solvepde" to prescribe the boundary condition.

I have also another question sorry.

Is it possible to insert in the coefficient a the second derivatives of the dependent variables? (considering that I am trying to solve a system of three equations, I have in one equation a term )

a can depend on x, t and u, but not on the derivatives. The only thing you can try is to put the term in the flux part (div(c*grad(u)).