Fcap (1 cos 45)
cap (sin 45)
Figure 4.21 Free body diagram of rigid cap with algebraically summed pretension force
components
Forces act on nodes
around entire
circumference
Figure 4.22 Force components applied to finite element model of rigid connector
4.3 Top-Down Flow Cage Model
In the top-down flow model, the center tube is anchored at the top of the cage
with flow in the opposite direction. Small frictional drag occurring along the center tube
is neglected because it lies in the direction of flow. To save on computing time, the
center tube is eliminated from the model and replaced with a single node at the top and
bottom of the cage.
Although not immediately obvious, symmetry could be not be used to simplify
the top-down flow cage model analysis. Dividing the cage along the x, y, or both the x
and y axes does not work because the state of bending makes the z-direction boundary