Modeling Objectives & Problem Description - Lesson 1

Learning Goals

In this tutorial, you will learn to:

• Create a mesh for a three-dimensional internal flow.
• Apply Non-Newtonian fluid properties using the Carreau model.
• Apply time-varying boundary conditions using User Defined Functions (UDF).

Problem Specification

Consider the following 3D model of a carotid artery bifurcation.

This model is created from a luminal casting of a carotid artery bifurcation and generously shared in Grabcad community

https://grabcad.com/library/carotid-bifurcation

Blood flows through the bifurcating artery from the inlet (to the left in the graph above) and exits from the two outlets (to the right). The diameter of the artery at the inlet is around 6.3 mm. The diameter of outlet 1 is around 4.5 mm and the diameter of outlet 2 is around 3.0 mm. The density of blood is 1060 kg/m³ [1]. As blood is a non-newtonian fluid, the coefficient of viscosity of blood is not a constant, but rather, it is a function of velocity gradients. Here we use the Carreau-model to model blood’s viscosity. Since blood flow is pulsatile and cyclic, the velocity profile at the inlet is a function of time. The pressure at the outlet is defined to be constant (100 mm Hg). More details on boundary conditions will be provided in the next lesson "Pre-Analysis and Set-up".

The summary of steps for ANSYS Workbench version 19.2 can be found below.