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# Looking for Cd and Cl vs AoA for flat plate.

## Looking for Cd and Cl vs AoA for flat plate.

(OP)
Hello,

I have searched the interwebs looking for this data and I cannot find it. I need Cd and Cl for a flat plate through an entire 360 degree rotation of AoA, including different sets of curves for different aspect ratios up to infinity. If anyone has this data it will be greatly appreciated.

Thanks,

- D

### RE: Looking for Cd and Cl vs AoA for flat plate.

not sure which of the "interwebs" you were looking in but googling "flat plate lift" got a bunch of hits.

in part, i doubt anyone has exactly what you're looking for but you can start with the 2D result ... Cl = 2pi*(AoA), AoA in radians for small angles. using Cl = 2pi*sin(AoA) will be instructive.  the problem you face is separation (when does the flat plate stall?) modifying this 2D result for 3D is easy, and is in just about every undergrad aerodynamics text.

"flat plate drag" also gave numerous hits.

### RE: Looking for Cd and Cl vs AoA for flat plate.

(OP)
Hello, thank you for the response.

Ahh but herein lies the problem. They have flat plate data but not for a full 360 rotation. Maybe 0-18 degrees from what I have seen. I have googled everything regarding the flat plate vs. AoA from 0-360 and I cannot find that data.

### RE: Looking for Cd and Cl vs AoA for flat plate.

Why would you ever need a full 360 for this particular shape?

135° is the same orientation as -45°

You should not need anything beyond ±90°

### RE: Looking for Cd and Cl vs AoA for flat plate.

ditto to what IR posted, that was what i meant by using sin(AoA) for (AoA)radians.

if you open up your search parameters (to "flat plate lift") one hit i can remember was to a 0 to 360 Cl plot for a NACA 0015 airfoil ... not exactly what you want, i know.

Depends on what you want it for ... how accurately you want it ?  a reasonable estimate is for -18<AoA<18deg, CL = 2pi*sin(AoA0 and zero elsewhere.  separation isn't exactly at 18deg, varies with reynolds number (researching this specifically'll probably get you some useful results), post-separation lift isn't exactly zero, pre-reattachment lift isn't exactly zero.

if you want exact data, i suggest you experiment and create it yourself ... a nice undergrad project.

### RE: Looking for Cd and Cl vs AoA for flat plate.

(OP)
Yes in essence 0-90 would be sufficient. The reason I wanted 0-360 data is because our company is designing a water turbine and the blades will undergo incidences in all regimes.

I cant even find 0-90 data on a flat plate, such a basic and fundamental shape yet there is only data on this thing until stall. I have searched all over and I only found data for a NACA0012 and NACA0015 for a full 360 degree sweep AoA. After about 20 degrees it will behave like a flat plate but I'd rather have flat plate data at these angles if they exist somewhere. Thanks

### RE: Looking for Cd and Cl vs AoA for flat plate.

not sure how much flat plate data will help you ... you could use fliud momentum to get some idea of forces expeienced with separated flow.  my thought, FWIW, is that in a turbine there are going to be many other significant effects ... radial flow, wakes, cavitation, ...

### RE: Looking for Cd and Cl vs AoA for flat plate.

A ways late but that info you were looking for is right here.

http://cwrowley.princeton.edu/papers/Taira_reno07.pdf

Comprehension is not understanding. Understanding is not wisdom. And it is wisdom that gives us the ability to apply what we know, to our real world situations

### RE: Looking for Cd and Cl vs AoA for flat plate.

(OP)
Hello castmetal,

I have read that document, the problem is it is for very low reynolds numbers and doesnt really apply to me.

Thank you anyway

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