Hi, why an Error occurred while flattening??
model betondechanvreFINAL
parameter DomainLineSegment1D wall (L=0.36,N=20) "domain";
field Real teta (domain=wall);
field Real T (doamin=wall);
parameter Real rholiquid = 1000; //material density rholiquide beton de chanvre
parameter Real rhosurface = 0.011;//material density du beton de chanvre
  parameter Real rhogaz = 0.011; //material density du beton de chanvre
  parameter Real Rhoambiant = 1.25; //material density de l'air
  parameter Real Cp = 1000; //specific heat capacity
  parameter Real L = 0.36; //length of the wall
  parameter Real lambda = 0.1; //heat conductivity
  parameter Real Tinit = 296.15;//the wall is at 20 degree initialy
  parameter Real Text = 303.15; //the wall is at 20 degree initialy
  parameter Real tetainit = 0.012; //the wall is at 40% final relative humidity
  parameter Real Tfinal = 303.15; //the wall is at 30 degree final
  parameter Real Dteta = 1.16e-9;
  parameter Real Dtemp = 1.02e-12;
  parameter Real Dtetav = 1.07e-9;
  parameter Real Dtempv = 1.02e-12;
  parameter Real Lv = 2500; //specific heat capacity
  parameter Real hMassique = 0.0025;//coefficient d'echange massique
  parameter Real coefficientThermique = 3; //heat transfert coefficient intern

initial equation//initialise the state of variable of the module
T=Tinit indomain wall;
teta=tetainit indomain wall;

equation
der(teta)=Dtemp*pder(T,x2)+Dteta*pder(teta,x2) indomain wall;
rhogaz*Cp*der(T)=lamb*pder(T,D,x2)+Lv*rholiquid*Dtempv*pder(T,x2)+Dteta*pder(teta,x2) indomain wall;

//boundaries
-rholiquid*Dtemp*pder(T,x)=0 indomain wall.left;
-rholiquid*Dtemp*pder(T,x)-rholiquid*Dteta*pder(teta,x)=hMassique*(rhosurface-Rhoambiant) indomain wall.right;
end betondechanvreFINAL;