FVUS - Finite Volume Utilities and Solvers

A finite volume framework for multiphysics solvers

What is FVUS/Wildkatze?

FVUS is collection of libraries and solvers for performing multi-physics simulations. FVUS aims to provide rich set of physics models to users along with a flexible framework to add their own. High performance is achieved through data parallelization using MPI.

Vortex Shedding

Vortex shedding behind an object.


VOF Test Case.

Bubble Rising in liquid

A validation test case for VOF and surface tension.

FVUS Features

Quick summary of important features of FVUS/Wildkatze solver.


Wildkatze solves flow in a segregated manner using SIMPLE (Semi Implicit Pressure Linked Equations) method.

Immersed Boundary Method

Immersed Boundary framework is provided. In a normal Immersed Boundary method implementation, flow region is marked by immersed region and then velocity is imposed upon this marked region. In FVUS framework, marked region creates a Partial Region. This partial region is then used to apply different physics models to it. To our knowledge no multi-physics solver in market has this capability.

Volume of Fluid Multiphase Model

Volume of fluid model with multiple phases is available with incompressible phases. Surface tension forces are modelled with Continuum Surface Stress model. This model avoids calculation of curvature needed for Continuuum Surface Force model. Hence it performs better near walls with sharp angles.

Multi-Region Support

Another unique feature to FVUS is its ability to apply different physics models to selected sets of multi-regions. User is allowed to create any number of sets of regions. User can chose to apply different physics models to these region sets. It opens up lots of possibilities for customising solver. For example user can use LES model in one region and K-Omega turbulence model in another. It is a powerful feature and should be handled with care.

Multi-Phase Support

Like multi-region, an user can define any number of phases. Then could go on to create various sets out of these phases. Various physics models then could be defined using these region sets and phase sets.

Fine Grain Control Over Physics Models

One of the reasons why FVUS is better at customized research is that it provides user much more control over solver options. For example in most of the commercial solvers if user chooses an unsteady marching scheme (example Implicit Euler ) he is stuck with the same scheme for all the physics model he is going to use in this simulation. In FVUS user can use different time stepping schemes in each model. Similarly user could use different gradient computation schemes for each model. (Not possible with most of commercial software).

User Coding and User Model

FVUS provides User Model which could be completely shaped by user coding. In user coding FVUS provides user access to almost every variable and settings that solver uses internally. Efforts are put to make this access easier. This helps user do his own research within Finite Volume framework. For details please contact support team.


Various turbulence models are provided: Spalart Almaras model, SST - K Omega turbulence model, Kinetic energy formulation based LES model. Smagorinsky LES subgrid model etc.

Compressible Flow

Compressible high spead flow for ideal gas law is provided.

Energy Model

Energy model is provided for non isothermal simulations.


Currently in progress

Mixture Multiphase Model

Eulerian multiphase model, where interface between various phases is not resolved like Volume of Fluid method.

About Us

Dravvya Simulations and Engineering Pvt. Ltd.

The origins of project FVUS lie in previous project by author called iNavier. While iNavier was single region, single phase solver that could only run simulations in serial machines, Wildkatze (FVUS) could run calculations on multi-region, multiphase and on parallel machine.

Even though FVUS/Wildkatze has its roots in iNavier, the project was completely written from scratch. The coding started in January 2015. FVUS Gui was started in August 2015 to help setting up calculations and it grew up to be independent project.

Company Dravvya Simulations and Engineering is established to take this software further.

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