We are trying to do blood flow simulation on a vessel geometry model. When we try to apply Womersley boundary condition to the inlet, we meet some problems.

In Womersley boundary condition, we need to specify the property "axispoint" which should be the center of the vessel's inlet and the property "axisnormal" which should be the flow direction. However, we can only estimate these two value because they are not in the standard position(all the numbers are floating points). This causes the failure of simulation. So I want to know does Nektar++ require 100% accuracy in these two property? If so, does anyone have some suggestion? 

Many thanks!

Best,

Zhen