Non Orthogonality issue

Hi there,

I have the following project here and wanted to check the quality of the mesh. The Non Orthogonality max value is 76 which is larger than the recommended value in the documentation. (<<75)

Could anyone help me with a method to reduce this value please?


A maximum non orthogonality of 76 is definitely acceptable for current CFD solvers. Have you already tried to run a simulation to see if you run into problems?

Depending on the complexity of your CAD model, reducing the max non orthogonality much further may not be possible, unless you defeature the details too much (which may defeat the purpose of the analysis).


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Hi there,

I have not yet run a simulation as i thought the 76 was unacceptable. The cad model is very basic (a simple tall building) I will run the simulation and see if there are any problems.

Thank you for the help!

As @RicardoParis mentioned, for incompressible solvers for a single-phase flow, it should not be an issue. Still, if the solution starts to diverge check out this post: Post. Start by adding a non-orthogonal correction.

Happy CFDing,



Hi sir i have question, if the non orthogonal value is 89 and the most of the residual are below 1e-3 but only the pressure residual graph is between 1e-2 and 1e-3 , can i consider the simulation result as almost convergent

For a max non ortho of 89, it’s usually better to pinpoint the problematic cells and improve the mesh/CAD model around that region.

In any case, from a convergence point of view, it’s impossible to judge convergence exclusively from residuals. This page goes through more details: How to Check Convergence of a CFD Simulation? | SimScale

ok thank you sir