Numerical simulation of blood flow in a venular bifurcation

Results from a three-dimensional numerical model simulating blood flow in a single venular bifurcation are presented. A side and main branch, each containing fluid with a unique viscosity (and, therefore, unique hematocrit, are fused to form an outlet branch which contains both fluids flowing together. Solving this problem using the finite element method has demonstrated that flow is strongly influenced by viscosity ratio between the merging fluid streams. As viscosity from the side branch is increased relative to that of the main branch, the interface formed between the two fluids bulges farther away from the side branch orifice. The less-viscous fluid has the highest radial velocity gradients at the outlet branch and tends to surround the fluid with higher viscosity, leading to asymmetric velocity ratio and spatial location in the vicinity of the bifurcation. These findings have important implications in post-capillary resistance, metabolic transport, and various flow phenomena associated with venules.