Spatial Convergence Order of Unsteady Problems

[qk11853]

N = N * 2
mesh = UnitSquareMesh(N, N, diagonal="crossed")

# ====================Time===================
dt = 1e-5
num_steps = 10
T = dt * num_steps

I get an error when using finite element method to find the spatial convergence order. I give a very small time step and reduce the spatial step by half each time. Why can't I get the correct convergence order?

[connorjward]

Please share a complete (minimal) script that reproduces the error, as well as the error message. The information you have provided isn't enough for us to help you.