The basic differential equation of the deflection of a simply supported, uniformly loaded beam is given as (deflection is represented by the curved dashed line in the Figure):
EId^4y/dx^4 - WLx^2w(x) = 0
where, E = the modulus of elasticity and I = the moment of inertia. The boundary conditions are y(0) = y(L) = 0. The following parameter values apply: E = 200 GPa, I = 30,000 cm^4, w (uniform load) = 15 kN/m, and L = 2 m. Using the finite-difference approach (Ax = 0.5 m), calculate the deflection of the beam (y) at locations 1.0 m and x = 1.5 m and evaluate the percent true relative error if the analytical solution is:
y(x) = (WLx^3)/(12EI) - (WLx)/(24EI)
Creeping oil flow underground can be modeled (in 2 dimensions) as driven by an effective pressure (p) as:
(d^2p/dx^2) + (d^2p/dy^2) = 0