## Fluids

Topics relate to Fluent, CFX, Turbogrid and more

#### Uniformity Index in CFD-Post

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• bsmith643
Subscriber

Does anyone know if it's possible to get uniformity index in CFD-Post without creating a new expression?

It's easy to obtain in Fluent (just go to surface integrals and select uniformity index), but there doesn't seem to be an equivalent calculation built into CFD-Post, and I'd like to use Post since it loads and handles my model much faster.

• CFD_Friend
Ansys Employee

Hi,

There is no direct function available to calculate the uniformity index. However, we can create a similar expression to calculate the uniformity index value using other functions available in POST. The uniformity index depends on the average value of a property in a sectional area. We can achieve the same result by leveraging the functions provided in CEL.

To illustrate this, let's take an example of calculating the uniformity index of velocity at the outlet:

1. First, we calculate the average velocity at the outlet: AV1 = areaAve(Velocity) @ Outlet

2. Next, we compute the numerator of the uniformity index equation: Numerator = sum(abs(Velocity - AV1) * Area) @ Outlet

3. Then, we determine the denominator of the uniformity index equation: Denominator = 2 * abs(AV1) * area() @ Outlet

4. Finally, we can compute the uniformity index: Uniformity index = 1 - (Numerator / Denominator)

I recommend applying these expressions to a test case available in Fluent to verify the correctness of the approach.