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 jyh3134 January 30, 2013 11:40

calculate pitching moment coefficient

Hi all,
I'm studying 3D wingbody currently to get CL,CD,CM.

In my results, CL,CD is acceptable compared to reference data.
(each error is less then 10%)

But CM, pitching moment coefficient is very far from reference.
(error is over 300%)

So i doubt my process to getting CM.

First, reference paper said
- Reference length(mac) : 0.6m
- Moment reference point : 0.45m
- Moment reference y-loc : 0.023m (down)

So, I set the 'reference values' in Fluent
- Length : 0.6m
- and velocity, area
And created 'moment monitor',
Moment center => x : 0.45, y : -0.023
Moment Axis => z : -1 (for left-hand direction of nose-up)
Wall zones : All surfaces of wingbody.

and ran simulation.

Am I right? How can be getting very far CM in spite of close CL and CD?

Best Regards

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