Make pressure clipping in BoundaryModelDummyParticles optional

[efaulhaber]

Pressure clipping is not a correct formulation, it is just a workaround to avoid sticking artifacts.
Away from free surfaces it leads to artificially increased boundary pressures that cause larger gaps between fluid and boundary in areas of low pressure, against which the particle shifting technique is fighting.

This PR adds an option to disable clipping, which should be enabled for closed systems.

[codecov]

Codecov Report

❌ Patch coverage is 86.66667% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.19%. Comparing base (da45b6f) to head (79d51de).

Files with missing lines	Patch %	Lines
.../schemes/boundary/wall_boundary/dummy_particles.jl	86.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1143      +/-   ##
==========================================
- Coverage   89.19%   89.19%   -0.01%     
==========================================
  Files         128      128              
  Lines        9919     9927       +8     
==========================================
+ Hits         8847     8854       +7     
- Misses       1072     1073       +1     

Flag	Coverage Δ
total	89.19% <86.66%> (-0.01%)	⬇️
unit	67.64% <86.66%> (+0.03%)	⬆️

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[Copilot]

Pull request overview

This PR makes negative pressure clipping in BoundaryModelDummyParticles configurable so it can be disabled for closed-system simulations where clipping would be physically incorrect and can introduce artifacts.

Changes:

• Added a clip_negative_pressure keyword (default true) to BoundaryModelDummyParticles and threaded it through the model type for compile-time branching.
• Updated boundary pressure computation to conditionally clip negative pressures (both for state-equation-based pressure and Adami extrapolation).
• Added tests covering clipping on/off behavior and ensuring the setting survives Adapt.adapt.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/schemes/boundary/wall_boundary/dummy_particles.jl	Adds optional negative-pressure clipping to BoundaryModelDummyParticles with a static (type-parameter) flag used in pressure update paths.
test/schemes/boundary/dummy_particles/dummy_particles.jl	Adds unit tests validating clipping behavior for multiple density calculators and through Adapt.adapt.

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[svchb]

What is supposed to happen when clipping in the state equation is activated and deactivated here?

[efaulhaber]

When clipping in the state equation is activated, then pressure is clipped everywhere and it cannot become negative anyway, except perhaps with Adami when the boundary is accelerated away from the fluid.

[svchb]

But shouldn't this be an error than or warning?

[efaulhaber]

But shouldn't this be an error than or warning?

Why? Everything is working as expected.

[svchb]

Because the inconsistency might be confusing.

[efaulhaber]

I don't see an inconsistency. Enable pressure clipping for the boundary model to clip boundary pressure. Enable pressure clipping of the state equation to enable global pressure clipping.

[svchb]

Ok than just adjust the docstring also for state equation pressure clipping.