SimScale CAE Forum

Aircraft wing spoiler

Hi, I am working on a designing an aircraft spoiler. I would like to run simulation to it. But I have very little knowledge on SimScale. This is my first project working with CFD. I would love to talk to somebody that can guide me in the right direction. Here is the project if you would like to take a look. https://www.simscale.com/projects/sasidokuburra/aircraft_wing_spoiler_1/
Thank you.

Regards,
Sasi.

Hi @sasidokuburra,

For your first project using CFD I suggest first to learn how to correctly simulate an aircraft wing. You can find some good examples in project space of SimScale. It could take few weeks minimum. You will feel at easy after few months.

Your current project with 20 degree tiny spoiler is very difficult due to shape of the spoiler (3 mm thick), emboss on the wing left by the open spoiler, span of the wing (~1.2 m) compared to the spoiler. Difficulty comes already from meshing, as you will have enormous ‘aspect ratio’ of mesh cells (ratio of smallest mesh cell to biggest cells).

As a result, creating right mesh will consume your core-hours quickly…

My advice would be to use ‘quasi-2D’ approach and not start with full 3D simulation. In that case, you take a wing ‘section’ of, say, 5 o 10 cm only, having that spoiler in. Meshing and first simulation results will be quick, comparing different angles would be possible, you will not exhaust your core-hours in couple of weeks.

However @DaleKramer or @dschroeder can give better advice.

Take care,

Retsam

Hi @sasidokuburra

As Retsam said, a thin slice of the geometry is definitely the way to start so you dont burn through core hours. Also the small flap will be difficulty to accurately mesh however it is not impossible. I would suggest getting used to simscale by meshing only the wing profile and adding the flap after you are more comfortable. In addition, here are some suggestions for your geometry to avoid meshing issues:

  1. When you do add the flap, small gaps will cause problems, these must be filled (BLACK). The face between the end of the flap and the profile must also be filled (RED). Finally, the mesh doesnt like sharp surfaces as it will try to decide which surface to snap too, this requires the (BLUE) are to be filled as shown as in, create a chamfer between the flap and wing profile.
    image

  2. On the trailing edge of the wing, the face seems to become smaller going to one side, im not sure if this was intentional but the there are a few options for this area.
    a. thicken the trailing edge so that the cells can cover this area without snapping issues (3-5mm)
    b. make the trailing edge sharp so there is no face at all
    c. Split the geometry into two faces so you can apply a higher cell refinement to this area

In the end simulation will take a while to get used to. I would also highly suggest watching some tutorials or videos to understand the basics. I suggest the FSAE videos because it goes through the basics of aerodynamics, meshing, and simulation Here

Good Luck

Dan

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Hi Dan,

Thank you for your response. Sorry for responding late.

Thank you for taking time and looking into my design and giving me your insights. I really appreciate it.

The wing and a spoiler creates and reduces a value of lift and drag. I am seeking to find those values. For an aircraft with a spoiler, it should have clearance gaps to operate. How can I get accurate data with no gaps? Correct me if I am wrong. Thank you.

Regards,
Sasi.

Hey @sasidokuburra

I am also sorry for the late reply as i recently moved and had no internet.

If you are talking about the gap between the wing and spoiler that is needed so that they can move in realty then I would remove this. I am guessing this kind of gap would be in the 1-3mm range so that the two parts physically dont touch and can actually move.

If you are talking about a slot gap - as in when the spoiler is retracted on an airplane so that air passes through the slot and re-energizes the boundary layer … then yes you should simulate this kind of gap ( normally 10mm or larger).

based on your geometry, you are talking about the first scenario and the quality reduction from trying to mesh this small gap correctly will result in less accurate data then if your were to just delete it.

Simulation is never 100% accurate and achieving a balance between the accuracy of the model and the quality of the mesh is hard to find. Normally compromises must be made to get any kind of result, so you should expect a margin of error

Dan

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