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Changelog

TrixiParticles.jl follows the interpretation of semantic versioning (semver) used in the Julia ecosystem. Notable changes will be documented in this file for human readability.

Version 0.4.1

Features

  • Added an incompressible SPH solver ImplicitIncompressibleSPHSystem (#751).
  • Added SplitIntegrationCallback to integrate the TotalLagrangianSPHSystems in a Semidiscretization separately from the other systems (#794).

Important Bugfixes

  • Fixed kernel_grad threshold with single precision and small particle spacing (#913).
  • Fixed error with UpdateCallback when SaveSolutionCallback comes first in the CallbackSet (#924).
  • Fixed error when using shifting techniques without UpdateCallback (#925).
  • Updated program flow diagram (#917).

Version 0.4

API Changes

  • Renamed BoundarySPHSystem to WallBoundarySystem and the keyword argument movement to prescribed_motion.

  • Renamed OpenBoundarySPHSystem to OpenBoundarySystem.

  • Renamed BoundaryMovement to PrescribedMotion. The movement_function must now be a function of (x, t) returning the new position instead of an offset. For example, movement_function(t) = SVector(t, 0.0) now needs to be movement_function(x, t) = x + SVector(t, 0.0).

  • Renamed directory solid to structure in the examples file tree. VTK files for the TotalLagrangianSPHSystem are now also called structure_*.

  • Renamed keyword argument n_fixed_particles of the TotalLagrangianSPHSystem to n_clamped_particles.

  • API for OpenBoundarySystem and BoundaryZone changed. It is now possible to pass multiple BoundaryZones to a single OpenBoundarySystem. Reference values are now assigned individually to each BoundaryZone. (#866)

  • Rename keyword arguments plane and plane_normal for BoundaryZone to boundary_face and face_normal (#597).

  • The argument of TransportVelocityAdami is now a keyword argument. TransportVelocityAdami(1000.0) now becomes TransportVelocityAdami(background_pressure=1000.0) (#884).

  • Combined transport velocity formulation (TVF) and particle shifting technique (PST) into one unified framework. The keyword argument transport_velocity now changed to shifting_technique. The ParticleShiftingCallback has been removed. To use PST, use the UpdateCallback instead, and pass shifting_technique=ParticleShiftingTechniqueSun2017() to the system (#884).

  • Renamed the keyword argument tlsph to place_on_shell for ParticlePackingSystem, sample_boundary, extrude_geometry, RectangularShape, and SphereShape (#814).

  • Custom quantity functions passed to SolutionSavingCallback or PostprocessCallback that were not using the documented API but were functions of (system, v_ode, u_ode, semi, t) now need to be functions of (system, dv_ode, du_ode, v_ode, u_ode, semi, t) (#879).

  • Renamed each_moving_particle to each_integrated_particle, n_moving_particles to n_integrated_particles and active_particles to each_active_particle.

Features

  • Added consistent particle shifting by Sun et al. (2019) as ConsistentShiftingSun2019 (#888).

Version 0.3.2

Features

  • Open boundaries:

    • Averaging of the inflow velocities has been added as an option. (#833)
    • New mirroring methods 0th order, 1st order and simple mirroring have been added. (#855)

  • TLSPH:

    • The option to add artificial viscosity has been added to increase stability of FSI. (#869)

Important Bugfixes

  • Fix the coordinates used for TLSPH in Adami extrapolation (#853)
  • Fix PST for small smoothing length factors (#834)
  • The TVF model has been improved to integrate correctly with time stepping (#864)

Version 0.3.1

Features

  • Simplified SGS Viscosity Models: Added ViscosityMorrisSGS and ViscosityAdamiSGS, which implement a simplified Smagorinsky-type sub-grid-scale viscosity. (#753)

  • Multithreaded Integration Array: Introduced a new array type for CPU backends that enables multithreaded broadcasting, delivering speed-ups of up to 5× on systems with many threads when combined with thread pinning. (#722)

  • Tensile Instability Control (TIC): Implemented TIC to mitigate tensile instability artifacts in simulations. (#769)

  • DXF file format support: Import complex geometries using the DXF file format. (#821)

  • Improved Plane interpolation: Massively improved interpolation performance for planes (#763).

GPU

  • Make PST GPU-compatible (#813).

  • Make open boundaries GPU-compatible (#773).

  • Make interpolation GPU-compatible (#812).

Important Bugfixes

  • Fix validation setups (#801).

  • Calculate interpolated density instead of computed density when using interpolation (#808).

  • Fix allocations with Julia 1.10 (#809).

  • Fix Tafuni extrapolation for open boundaries (#829).

Version 0.3

API Changes

  • Rescaled the Wendland kernels by a factor of 2 to be consistent with literature. This requires adjusting the previously used smoothing length for the Wendland Kernels by dividing them by 2 as well to obtain the same results (#775).

  • API for custom quantities and functions in the PostprocessCallback changed (#755).

  • The API for choosing parallelization backends changed. The keyword argument data_type in semidiscretize was removed and a keyword argument parallelization_backend was added to Semidiscretization. See the docs on GPU support for more details.

Features

  • Explicit Contact Models: Added explicit contact models, LinearContactModel and HertzContactModel, to the DEM solver. (#756)

  • Particle Shifting Technique (PST) for Closed Systems: Integrated the Particle Shifting Technique to enhance particle distribution, reduce clumping and prevent void regions due to tensile instability in closed system simulations. (#735)

  • Open Boundary Model: Added an open boundary model based on Tafuni et al. (2018), utilizing mirroring and extrapolation to transfer fluid quantities to the buffer zones. This enhancement allows for more accurate handling of simulation boundaries in open systems, ensuring better consistency between the computed domain and its buffer areas. (#574)

  • Transport Velocity Formulation (TVF) for WCSPH Solver: Added support for TVF to the WCSPH solver, improving the consistency and stability of weakly compressible SPH simulations. (#600)

Refactoring

  • Variable Smoothing Length Structures: Introduced new structures to support a variable smoothing length, providing enhanced flexibility in simulation configurations. (#736)

  • Flexible Parallelization Backend: Improved the parallelization backend support, making it possible to switch the parallelization backend for single simulations. (#748)

  • Total Lagrangian SPH: Added per-particle material parameters. (#740)

Version 0.2.7

Features

  • Added the classic Continuum Surface Force (CSF) model based on Morris 2000 (#584), which computes surface tension as a body force proportional to curvature and directed along the interface normal. This method is efficient and accurate for capillary effects but does not explicitly conserve momentum.

  • Added the classic Continuum Surface Stress (CSS) model based on Morris 2000 (#584), which is a momentum-conserving approach that formulates surface tension as the divergence of a stress tensor. However, it requires additional computation and stabilization to handle high-density interfaces and reduce numerical instabilities.

  • Added BoundaryZone to allow for bidirectional flow (#623)

  • Added the symplectic time integration scheme used in DualSPHysics (#716)

Documentation

  • Added documentation for time integration (#716)

Testing

  • Run CI tests on GPUs via Buildkite CI (#723)

Bugs

  • Fix GPU computations (#689)

Version 0.2.6

Features

  • Support for surface tension was added to EDAC (#539)

Refactored

  • Surface normal calculation was moved from surface_tension.jl to surface_normal_sph.jl (#539)

Version 0.2.5

Features

  • Add particle packing for 2D (.asc) and 3D (.stl) geometries (#529)

Compatibility Changes

  • Dropped support for Julia 1.9

Version 0.2.4

Features

  • A method to prevent penetration of fast moving particles with solids was added (#498)
  • Added the callback SteadyStateReachedCallback to detect convergence of static simulations (#601)
  • Added ideal gas state equation (#607)
  • Simulations can be run with Float32 (#662)

Documentation

  • Documentation for GPU support was added (#660)
  • A new user tutorial was added (#514)
  • Several docs fixes (#663, #659, #637, #658, #664)

Version 0.2.3

Highlights

Transport Velocity Formulation (TVF) based on the work of Ramachandran et al. "Entropically damped artificial compressibility for SPH" (2019) was added.

Version 0.2.2

Highlights

Hotfix for threaded sampling of complex geometries.

Version 0.2.1

Highlights

Particle sampling of complex geometries from .stl and .asc files.

Version 0.2.0

Removed

Use of the internal neighborhood search has been removed and replaced with PointNeighbors.jl.

Development Cycle 0.1

Highlights

Discrete Element Method

A basic implementation of the discrete element method was added.

Surface Tension and Adhesion Model

A surface tension and adhesion model based on the work by Akinci et al., "Versatile Surface Tension and Adhesion for SPH Fluids" (2013) was added to WCSPH.

Support for Open Boundaries

Open boundaries using the method of characteristics based on the work of Lastiwka et al., "Permeable and non-reflecting boundary conditions in SPH" (2009) were added for WCSPH and EDAC.

Pre Initial Release (v0.1.0)

This section summarizes the initial features that TrixiParticles.jl was released with.

Highlights

EDAC

An implementation of EDAC (Entropically Damped Artificial Compressibility) was added, which allows for more stable simulations compared to basic WCSPH and reduces spurious pressure oscillations.

WCSPH

An implementation of WCSPH (Weakly Compressible Smoothed Particle Hydrodynamics), which is the classical SPH approach.

Features:

  • Correction schemes (Shepard (0. Order) ... MixedKernelGradient (1. Order))
  • Density reinitialization
  • Kernel summation and Continuity equation density formulations
  • Flexible boundary conditions e.g. dummy particles with Adami pressure extrapolation, pressure zeroing, pressure mirroring...
  • Moving boundaries
  • Density diffusion based on the models by Molteni & Colagrossi (2009), Ferrari et al. (2009) and Antuono et al. (2010).

TLSPH

An implementation of TLSPH (Total Lagrangian Smoothed Particle Hydrodynamics) for solid bodies enabling FSI (Fluid Structure Interactions).