I am trying to solve a set of PDEs coupled with one ODE. I was able to solve the system of PDEs assuming the variable defined by the ODE stays constant. However, when I try to add the ODE, I am getting a syntax error. To reproduce the error, I have added a minimal script to just solve the ODE. I tried to follow the example in the post Can one solve system of ODE with fenics?. But I get a syntax error for my problem. Here is a minimal code.
from fenics import * mesh = IntervalMesh(200, 0, 2) V = FunctionSpace(mesh,'CG',1) v = TestFunctions(V) u = Function(V) dp = Constant(0.002) # Diameter of catalyst particle m eps = Constant(0.40) # epsilon muf = Constant(3.78E-5) # Average viscosity of gas, Pa.s rof = Constant(1565.85) # Average density Vz_in = Constant(1.0) # Inlet superficial velocity m/s P_in = 5.0E+5 # Inlet Pressure Pa bc = DirichletBC(V,P_in,'near(x, 0)') F_P = u.dx(0)*v*dx + (150*(1-eps)**2*muf/(dp**2*eps**3))*Vz_in*v*dx + \ 1.75*(1-eps)*rof*1e-3*Vz_in**2/(dp*eps**3)*v*dx
TypeError Traceback (most recent call last) <ipython-input-19-399fb5bf64b8> in <module> ----> 1 F_P = u.dx(0)*v*dx + (150*(1-eps)**2*muf/(dp**2*eps**3))*Vz_in*v*dx + \ 2 1.75*(1-eps)*rof*1e-3*Vz_in**2/(dp*eps**3)*v*dx TypeError: can't multiply sequence by non-int of type 'Indexed'
Can you please help me identify the issue?