Which scheme has been used to discretize the convective term in this equation:Fe2(ϕP+ϕE)−Fw2(ϕW+ϕP)=De(ϕE−ϕP)−Dw(ϕP−ϕW){"version":"1.1","math":"\frac{F_e}{2}(\phi_P+\phi_E)-\frac{F_w}{2}(\phi_W+\phi_P)=D_e\left(\phi_E-\phi_P\right)-D_w\left(\phi_P-\phi_W\right)"}