This work illustrates the behavior of the interstitial pressure and of the interstitial fluid motion in tumor cords (cylindrical arrangements of tumor cells growing around blood vessels of the tumor) by means of numerical simulations on the basis of a mathematical model previously developed. The model describes the steady state of a tumor cord surrounded by necrosis and its time evolution following cell killing. The most relevant aspects of the dynamics of extracellular fluid are by computing the longitudinal average of the radial fluid velocity and of the pressure field. In the present paper, the necrotic region is treated as a mixture of degrading dead cells and fluid.