Meshing airfoil


I am trying to create a mesh of all quadrangle faces around an airfoil. I am eventually going to be running this in openfoam. However, salome’s standard settings create triangles close to the wall of the airfoil.

I tried using quadrangle preference instead of standard for the 2D hypothesis, but the mesh keeps becoming inverted.

I also tried doing a viscous layer, but this just shifts the triangular section outwards.

Is there a way to fix these areas to only have quadrangle faces.

Quadrangle Preference:

Viscous Layer:

Did you try to add sub-mesh using your edge with an appropriate wire Discretisation then re-compute your mesh? This could potentially constrain your meshing computing.

I have four submeshes dividing the entire region into quadrants with the origin being the trailing edge of the airfoil.

Each quadrant is set as:
2D: quadrangle mapping with quandrangle standard
1D: wire discretisation with number of segments 200, scale factor 600

The only difference between submesh is the directions of scaling, which are set to be denser closer to the airfoil wall

Hello Ben,

What’s happens if you create an edges groups from edge of your foil by sector (into your geometry if i understand well), then inside your mesh add submesh on which you impose the expected number of quadrangle on the edge of your foil with the option 1D wire discretisation ?
Normally this should force the number of nodes on your foil edge layer.

I looked into trying to make the 1D wire discretisation like you suggested, but I realized that my airfoil is made up of three splines(made from a control point text file) that eventually get partitioned into 4 total pieces. Unfortunately, this means that when I try to set the 1D wire disc. it puts X amount of elements on each piece and resets the scaling. Is there a way for me to recombine them into just 2 lines (top and bottom of the airfoil)?

Finally realized I could attach a larger file by doing this, so here is what my file looks like:

control points file:

so, going to go from the begining of the issue itself.
your problem (as you discrived later) it is an issue in regards to the number of elements on your edges ie., nodes. when you use a quadrangle 2D algorithm you should be able to have 4 edges and the opposite ones have the same number of nodes in total. if not, the algorithm will not necessarily fail but it will add other kinds of elements (or all quads but that have a different arrangement) you can control this in the parameters of the quadrangle 2D algorithm in the mesh definition.

once that said, you need to have the same number of edges and divide your geometry into quads so the algorimthm will behave as you want.

for your issue in the airfoil geometry itself. i recommend the following:
create only 2 splines using the upper and button points separatly (and I think from memory that you can control the tangency of the splines (important for the tip of it) if not i will try to create only one spline (you need to pay attention in the order of the points!) if you want that the airfoil follows exactly the points use interpolation instead of b spline. the first will pass thought all the points, the later will only be near them but it will be smoother. also keep in mind that the bsplines supports only up to 27 points interpolation has not this problem.
once you have a curve with one or two vertexes (depending if you did one or two splines/interpolations) you can place extra points over the curve, and then you can use partition over the curve/curves using the vertex. this will ‘cut’ your curve/curves into small chunks of it and then you will not have this problem anymore.

Unfortunately due to other parts of the project I need to create the airfoil with 3 splines. Is there a way for me to merge the splines together at the end, so that when I create groups, it only counts as one edge? I tried a wire but it still behaves as 3 separate edges during the grouping phase.

yes you can set the number of edges of a sub mesh, and from one side set for example 10 and for the other that has two edges that the some of the two are 10 also. this is way more hacky but it works.