Boundary integration of viscous forces

[DanielDoehring]

Building upon #1812 this PR adds the viscous drag and lift coefficients due to shear stress.

For the viscous NACA0012 test (changed elixir) we match the values given in https://doi.org/10.1016/j.amc.2017.07.020

for the viscous drag coefficient very well:

Reference: 1.275e−01, Trixi: 1.24758705e-01

For viscous lift:
Reference: −3.945e−03 Trixi: -5.66376473e-03

@Arpit-Babbar please have a look!

[github-actions]

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Created with ❤️ by the Trixi.jl community.

[DanielDoehring]

Hm, Aqua.jl errors with

Unbound type parameters detected:
[1] analyze(quantity::Union{typeof(enstrophy), AnalysisSurfaceIntegral{Semidiscretization, Variable}}, du, u, t, semi::SemidiscretizationHyperbolicParabolic) where {Semidiscretization, Variable<:VariableViscous} 
@ Trixi ~/work/Trixi.jl/Trixi.jl/src/callbacks_step/analysis.jl:685
Unbound type parameters: Test Failed at /home/runner/.julia/packages/Aqua/9p8ck/src/unbound_args.jl:28
  Expression: isempty(unbounds)
   Evaluated: isempty(Method[analyze(quantity::Union{typeof(enstrophy), AnalysisSurfaceIntegral{Semidiscretization, Variable}}, du, u, t, semi::SemidiscretizationHyperbolicParabolic) where {Semidiscretization, Variable<:VariableViscous} 
@ Trixi ~/work/Trixi.jl/Trixi.jl/src/callbacks_step/analysis.jl:685])

See

https://docs.juliahub.com/Aqua/Hav67/0.8.4/unbound_args/#Unbound-Type-Parameters

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.30%. Comparing base (b4fb1db) to head (36e8f4e).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1893      +/-   ##
==========================================
+ Coverage   89.52%   96.30%   +6.78%     
==========================================
  Files         448      448              
  Lines       35995    36079      +84     
==========================================
+ Hits        32223    34745    +2522     
+ Misses       3772     1334    -2438     

Flag	Coverage Δ
unittests	96.30% <100.00%> (+6.78%)	⬆️

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[Arpit-Babbar]

Also, I think you could update the CI to test for the viscous forces before the PR is merged.

[DanielDoehring]

I added CI tests. Ready to go from my side, the open comments are meant to be explanatory for the reviewers.

[andrewwinters5000]

Looks quite good already, just a couple comments.

[DanielDoehring]

Hm, I do not understand why the testcase does not do the timestepping: https://github.com/trixi-framework/Trixi.jl/actions/runs/8569475328/job/23485450223?pr=1893#step:8:7498 🤔

Locally this runs perfectly fine, but in the CI not a single timestep is taken

[Arpit-Babbar]

Hm, I do not understand why the testcase does not do the timestepping: https://github.com/trixi-framework/Trixi.jl/actions/runs/8569475328/job/23485450223?pr=1893#step:8:7498 🤔

Locally this runs perfectly fine, but in the CI not a single timestep is taken

Could it be the same issue as this - #1812 (review)

The solution is given by Joshua below.

[DanielDoehring]

Could it be the same issue as this - #1812 (review)

The solution is given by Joshua below.

Ah yeah good idea, let's see what happens!

[andrewwinters5000]

LGTM!