Fluid through cylinder but not symmetric respect to y axis

1

Hi, I am interested in simulating flow through a square obstacle, where the square is not located at the center. I am using fenics tutorial as reference, except replace

# Define strain-rate tensor
def epsilon(u):
    return sym(nabla_grad(u))

by

# Define strain-rate tensor
def epsilon(u):
    return(nabla_grad(u))

since the system is no longer symmetric.

I am wondering if this is the right approach. Any help/references would be highly appreciated!