Robert S. asked 2 weeks ago
Hello
I have quesitions.
x, y panels increase, the more accurate it is?
Overall, the lift is lower and the drag is higher,
How many x y panels would it be accurate to use?
X panel as cos, y-panel as sin It shows better results.
1 Answers
techwinder Staff answered 2 weeks ago
Difficult question to answer.
In theory, the higher the panel density the better. Keep in mind however that this only influences the linear par of the solution. There are other approximations in the model which makes the search for high accuracy pointless. For instance:
- the mesh represents only approximately the actual geometry anyway
- the viscous and compressibility effects are ignored in the linear part of the problem
- the vortex or doublet densities are constant or at best linear on each panel
The main objective when building the mesh should be to make it
- reasonably representative of the actual geometry,
- robust and not subject to numerical instabilities,
- compatible with reasonable computations times, e.g. solutions should typically be computed in less than a minute
With that in mind, what I usually do is
- target 5000 to 10000 uniform elements,
- avoid small elements; COSINE distribution tends to create too small panels at the edges; TANH should be preffered
- try to have elements of same sizes where the fuselage connects to the wings
- more importantly: avoid having wake panels intersecting the downstream geometry
You can have a look at how I do it in the examples availble for download in the online documentation
André