Can Wind Tunnel Wall Corrections Improve Swept Wing Data Accuracy?

[RandomGuy88]

For my research I am going to be testing a swept wing in a wind tunnel. Currently I am looking into tunnel wall corrections and I was wondering if anyone knows of somewhere I can get uncorrected and corrected experimental data on a swept wing in a wind tunnel so that I can test out the correction methods.

Thanks

 

[boneh3ad]

Why correct the data? Instead, install wall liners that follow the streamlines and you will end up with an effectively infinite span.

 

[RandomGuy88]

What you mean infinite span? Do you mean the wing will have infinite span, because that is certainly not what I want. My model will be a reflection plane model and I need to correct measurements for wall interference.

I am not to familiar with wall liners but don't they take quite a bit of CFD work to design, and then they are really only useful for the angle of attack at which they were designed?

 

[boneh3ad]

Well I guess knowing a little more about your project would be helpful then. Could you describe this model a bit? In studying airfoils, there are very few instances where you don't want to be looking at the infinite span case. You generally want to be able to make measurements at a certain chord position and have them be independent of where you are in the span.

There are exceptions, but to advise you in that regard, I suppose I would need to know a little bit more about what you are attempting. What are you trying to measure exactly?

A bit more about wall liners: they are generally made of things like hard, dense foam and take the shape of the streamlines (since streamlines on a swept wing snake across the surface of the model instead of remaining in the same span position). This removes all wall effects except for those of the wall boundary layer, which is generally very thin. As a result, outside of that wall boundary layer, the flow is spanwise uniform and your measurements won't depend on where they are taken in the span. They do typically take a little CFD to design (or other documented knowledge of the streamlines) but it is generally a simple CFD case.

 

[RandomGuy88]

I will be testing a scaled down model of a full wing so it will have a finite span. It will be a semispan model mounted on the tunnel floor. I don't remember the exact geometric details off the top of my head but the sweep angle is approximately 37 degrees and the aspect ratio is around 6. It will be tested in a rectangular wind tunnel. I will be measuring lift, drag, pitching moment, surface pressure etc... all the normal things. But I will be particularly interested in the near and post stall regions. I will need to be able to correct the data for tunnel wall interference. I have been reading up on various methods to do this but I would just like some data that I could use as an example to ensure that I actually understand how to apply all of the corrections before I start writing my data reduction code.

 

[boneh3ad]

Well I suppose I don't really have any experience with that. Still, depending on how large the tunnel is and how large the model is, you may not even need to worry about it.