Version 2021.1

Released: 2021-06-08
Highlights: faster 3D, better GUI

  • Ability to load geometry with any number of triangles.
  • Spatial acceleration
    • Accelerated generation of boundary conditions for large meshes, improvement of >15% per time step.
    • Accelerated detection of points/walls collision for large time steps
    • Other geometrical manipulation is accelerated as well
  • Automatic initialisation of domain boundaries, based on bounds of input geometry.
  • Linear solvers are faster due to allocating solving memory only once.
  • Syntax highlighting for simulation input. Easier to write, and find errors if any.
  • Set free-slip boundary condition through boundary condition or coefficient as fluid property.
  • Fixed input and viscosity bugs for non-Newtonian models.
  • Option to render fluid points on top of the geometry, convenient for tanks/containers.
  • Slice operation shows the plane origin and normal when editing its parameters.
  • Added help about GUI, button in the application and a page on the website.
  • Due to the above, i.e. large rewrite, solver may be unstable before the next update.

Version 2020.4

Released: 2020-12-29
Highlights: 3D, non-Newtonian models

  • Added non-Newtonian models:
    • Bingham
    • Power Law
    • Cross-Power Law
    • Bird-Carreau
    • Casson
    • Mohr-Coulumb
  • Improved stability of the implicit velocity solver for flow near free surface.
  • Added 2nd order backward differencing (BDF2) for the implicit velocity solver. Only 1st order was available until now.
  • Added initial algorithm for dynamic (automatic) time stepping.
  • The solver now runs 3D problems in real-time.
  • Added the free-slip boundary condition.
  • Made the first round of optimizations in 3D collision detection of fluid and geometry.
  • GUI is upgraded with icon labels and 3D geometry rendering.
  • 3D camera zoom bugs are fixed.

Version 2020.3

Released: 2020-11-16
Highlights: Windows, implicit velocity solver, surface tension

  • Pressure gradient limiter to stabilise non smooth pressure fields.
  • Stabilised/improved source term for the pressure Poisson equation.
  • Implicit solution to the velocity with Jacobi solver and BDF1, stable high viscosities.
  • Improved Jacobi solver performance by average value of 7%.
  • Explicit curvature estimation at the free surface.
  • Surface tension force through pressure Dirichled b.c. (using curvature and Laplace jump).
  • Windows CPU support. GPU yields strange driver errors not experienced on Linux.
  • The domain acceleration may be imposed through timeline of positions, velocities or accelerations.
  • Fluid can be initialised in separate spaces by specifying multiple sources of flooding.
  • Added real-time colourisation by point’s IDs.
  • Added real-time colourisation of free-surface points.
  • Rendering of too fast simulations is limited to 60 FPS, to avoid losing performance on CUDA -> OpenGL transfer.
  • Added and tested Mohr-Coulomb non-Newtonian model.
  • Made research license a bit more flexible.

Version 2020.2

Released: 2020-05-10
Highlights: GPU, FEM, moving bodies

  • Enabled CUDA backend to run simulations on the GPU.
  • The movement of bodies may be imposed through timeline/keyframes of positions or velocities.
  • Smooth interpolation of imposed movement of bodies in time, using Piecewise Cubic Hermite Interpolating Polynomial (PCHIP).
  • Imposed body oscillations (along vector, or rotating along axis) are superposed to the movement, by using “impose_oscillation” input.
  • No more triangle soups, meshes now use connectivity information. This enables deformations, and easy orientation transformation.
  • Import surface meshes from OBJ, OFF or STL file formats. For STL (triangle soup) file format, connectivity is built upon loading.
  • Warning message is shown for users that have a too old GPU, that cannot view results in real-time.
  • Fluid-structure interaction using preCICE. Rhoxyz can be coupled with an external FEM solver. Tested using CalculiX solver.
  • Bodies marked using: “output_force”: true, export resultant force and torque acting on the body to a CSV file, each time step.

Version 2020.1

Released: 2020-02-15
Highlights: Initial public version