Need a better guess yo for consistent initial conditions_Error using daeic3 (line 230)

I am trying to solve coupled transient heat and mass transfer equations in 2D in a food material using the PDE toolbox (Matlab 2018b).

I am rgetting those errors :

Error using daeic3 (line 230)

Need a better guess y0 for consistent initial conditions.

Error in ode15s (line 313)

[y,yp,f0,dfdy,nFE,nPD,Jfac,dMfac] = daeic3(odeFcn,odeArgs,tspan,htry,Mtype,Mt,Mfun,...

Error in pde.EquationModel/solveTimeDependent (line 104)

sol=ode15s(fcn,tlist,uu0,odeoptions);

Error in pde.PDEModel/solvepde (line 54)

[u,dudt] = self.solveTimeDependent(coefstruct, u0, ut0, tlist, ...

Error in Riceheat_and_mass (line 66)

results = solvepde(riceHeatandMass,tlist);

What the errors mean and how to fix them. Details on the equations and the script are in the attachment.

Answer 1

[Pravin Jagtap]

Hello Fidele,

The approach followed by you in the attached script may not be the easiest way to solve this coupled system. To solve the system of coupled Partial Differential Equations we need to have both equations consistent with the form given in the documentation.

For better understanding of how to solve coupled partial differential equations refer following link:

https://www.mathworks.com/help/matlab/math/partial-differential-equations.html#brfhemi-1

The following link points have a similar example, which will probably help you in solving the problem.

https://www.mathworks.com/matlabcentral/answers/134654-simulation-of-coupled-partial-differential-equation-using-matlab

Kind Regards

~Pravin