Fig. 1

a shows the simulation setup and the differentiation between the two domains: the normal domain Ω_n (blue), which is equivalent to the fluid-carrying part, and the barrier domain Ω_b (white), where no fluid is present. b visualizes both the mean and covariance parts of the FEM mesh. In total, N_α=127 grid vertices and ψ basis functions are used for the covariance field in this example, and N_β=19 grid vertices and φ basis functions are used for the mean field