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.

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.

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.

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