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[Solution]

This example is taken from Cornell University’s ANSYS AIM Learning Modules

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Contents

1. Problem Specification
2. Geometry
3. Mesh
4. Physics Setup
5. Results Evaluation
6. Validation

Problem Specification

In this tutorial, flow through an aortic aneurysm will be modeled using Discovery AIM. An aortic aneurysm is an inflated section of the body’s main artery, called the aorta, which can lead to bursting of the artery and ultimately death.

Arteries carry oxygen-rich blood to various parts of the body at speeds of about 1.5 meters per second. Blood has an average density of 1060 [kg/m^3] and a viscosity of 1.5e-3 [Pa s].

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Geometry

Download the file here

In this video, you will learn how to import the CAD model.

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Mesh

In this tutorial, we will be using Physics-Aware Meshing. Physics-aware meshing helps automate and simplify your problem setup. With physics-aware meshing, the computational mesh is generated automatically based on the solution fidelity setting and the physics inputs.

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Physics Setup

In this video, you will learn how to define a new material for blood, and how to define fluid flow conditions.

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Results Evaluation

In this video, you will evaluate velocity vectors in the Aortic Aneurysm and pressure on the walls.

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Validation

In order to verify that the simulation is accurate, it must be compared to a study that is similar in nature. This tutorial will have its results compared with the results from a study done by the Team for Advanced Flow Simulation and Modeling (TAFSM). In a study called “Patient-Specific Computer Modeling of Arterial Dynamics and Blood Flow,” the TAFSM collaborated with researchers at Texas Medical Center to identify arterial data in different categories and demonstrate the effectiveness of computer modeling in those categories. One of these categories is the Abdominal Aortic Aneurysm, in which the aneurysm was created digitally and subjected to flow in order to predict the flow using two different computational methods. Both methods resulted the same plot, shown below, which can be compared to the AIM solutions due to the similarity in geometry.

 

Below is the plot output by Discovery AIM for the same situation.  As a qualitative comparison, it can been seen that the two plots are similar. There is an area of recirculation in the aneurysm, which is the key feature of aortic aneurysms. Further validation with experimental or other numerical results would be needed to assure the accuracy of the simulation.

Reference

Tezduyar, Tayfun E. “Patient-Specific Computer Modeling of Arterial Dynamics and Blood Flow.” Team for Advanced Flow Simulation and Modeling. Rice University, n.d. Web. 16 June 2017.