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

Problem Specification

In this tutorial, the velocity vectors, pressure profile and streamlines will be simulated in a 180 degree U-bend square duct. The material passing through the duct will be air with an intake velocity will be 12 m/s which is comparable to the speed of air in an office HVAC system. The geometry which we will be using is shown below, the inlet will be at the end of the longer section at the top while the outlet is the at the end of the shorter duct on the bottom.

Find the velocity vectors and pressure contour of the entire duct.

Geometry import

Download the file here

In this video, you will see how to import the geometry file in Discovery AIM.

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.

Physics Setup

In this video, you will learn how to define fluid flow conditions (inlet velocity, outlet pressure) to the flow volume.

Results Evaluation

In this video, you will learn how to view velocity vectors and total pressure in the flow domain.

Verification & Validation

A good way of validating the results from the simulation are by comparing them to an outside source which has computed results for the same scenario. In this tutorial, “Flow Through a 180 Degree U Bend” by Azore CFD Simulation Software will be compared to the simulation flow. Below is the flow visualization from the simulation from Azore.

This can be compared to our simulation by creating a velocity contour at the midplane created in the solution section previous. Add a contour at the plane and change the variable to velocity magnitude. In order for the results to be visualized the same, change the Coloring to Banded in the Appearance section. This contour is already shown in the results video. The contour is shown below and it validates our simulation. The velocity contours are extremely similar in both flow shape and velocity.

 Reference

“Flow Through a 180 Degree U Bend.” Flow Through a 180 Degree U Bend. Azore CFD Simulation Software,