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Riaan January 30, 2006 17:16

Spanwise Lift Distribution
Hello everyone,

I am currently working on a full 3D aircraft model (modeled with symmetry) - and I would like to know how I can extract the sectional (or spanwise) Cl (Lift Coefficient) loading?

I can make spanwise cuts on the wing, but it won't allow me to calculated forces on these cuts (effectively 2D airfoil curves).

vyom January 30, 2006 20:19

Re: Spanwise Lift Distribution
Hi Riaan, Even i am facing the same problem. If you get the way to find it, please do let me also know.

regards, vyom

MOHAMED HASSAN AHMED January 31, 2006 09:32

Re: Spanwise Lift Distribution
dear brother

make isosurface on the the section you want , and after the solving draw the lift and calculate the forces in the direction you want.

please sent to me the gambit journal.

with my best wishes mohamed hassan

Riaan February 1, 2006 10:37

Re: Spanwise Lift Distribution
Does this mean I have to make these surfaces BEFORE I run the solution? Why can't I just extract it from the converged solution?

Thanks for the offer, but I cannot send you my Gambit journal file - it is confidential.

Riaan February 2, 2006 11:11

Re: Spanwise Lift Distribution
Well, from the Fluent support guys - you need a UDF for this

Vyom February 2, 2006 17:08

Re: Spanwise Lift Distribution-Riaan
Hi Riaan, I havent used UDF and have no experience in it. Could you please help me in creating udf for the same.

regards, Vyom

Riaan February 2, 2006 18:13

Re: Spanwise Lift Distribution-Riaan
Well, I am also no expert in UDF - the tech support guys from fluentusers help me a lot. I will try to get it into Fluent this weekend and let you know.

Cheers Riaan

vyom February 2, 2006 22:45

Re: Spanwise Lift Distribution-Riaan
Hi Riaan, Thanks for the reply. I would highly appreciate your help.

regards Vyom

PEDRO FINO February 6, 2006 16:58

Re: Spanwise Lift Distribution
Hello everyone, I'm working on a project, it's about an agricultural aicraft and I have a problem, because, I need to calculate the lift distribution across the wing, and the worse part is that this wing has an aerodinamical and a geometryc twist.

if you can help me giving me some examples i'll apreciate it.

averis007 January 13, 2013 15:03

I know its almost 7 years to the original post, I'm writing this so people in future can use. In order to get the spanwise lift distribution, you have to create iso-surfaces at different spanwise locations of your choice. Generate xy plot for cp distribution, then manually calculate the value of local cl from excel or similar software. The catch is the data fluent will export will not have upper and lower surface separately, they will be mixed and you will have to manually find out which points lie on the upper surface and which on the lower. There will be no accompanying z coordinates to help you either. If you are going to extract data for a few geometries this will work, but if your work requires you to do it repeatedly for many geometries, I won't recommend this technique. In that case you should find some strategy to distinguish between upper and lower surfaces from the exported cp distribution data.

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