It is proposed to develop a general-purpose pressure-based Navier-Stokes solver on unstructured grids with a robust graphical user interface (GUI) that will meet the CFD requirements of the multi-disciplinary user groups of BARC that include design, experimentation, R&D and operation groups. The proposed solver would be able to carry out numerical simulations of fluid flow and heat transfer in an efficient and accurate manner.

The basic solver available with us has the following features.

1. Solves incompressible steady/unsteady flows in two- and three-dimensions.

2. Laminar and turbulent flows can be simulated. Reynolds-averaged Navier-Stokes equations (RANS) for turbulent flows with different two-equation models namely, κ-ε, κ-ω, Shear Stress Transport (SST) and Lam-Bremhorst models are implemented.

3. Ability to handle arbitrary polyhedral meshes. The solver can handle four types of elements, namely tetrahedrons, pyramids, prisms and hexahedral cells.

4. I/O (Input-Output) operations employ the nearly standardised CGNS (CFD General Notation System) file format. This is used both to input grid details into the solver and output the solution from the solver for visualization.

5. Finite volume method with collocated grid arrangement is used to discretize the governing equations with momentum interpolation to avoid pressure-velocity decoupling.

6. The user can solve for velocities, pressure, temperature and miscellaneous scalars.

7. Spatially and temporally varying boundary conditions (Dirichlet, Neumann, Robin and Convective Outflow) with user defined functions are implemented.

8. The user can choose one of the different convective discretization schemes: First order upwind (FOU), Blended scheme between FOU and CDS and bounded upwind-biased schemes (CUBISTA and CUI).

9. Conjugate heat transfer for solving combined heat transfer and fluid flow problems.

10. Natural convective flows at small and large temperature differences using an unified low Mach number algorithm.

11. MHD module with robust approach for high Hartmann numbers.

12. Multiphase flows (Gas-particle, Gas-Gas, Liquid-Liquid) can be simulated for a wide range of density ratios.

13. Radiative heat transfer module with surface-to-surface radiation as well participating media can be simulated.

14. Depending on the type of problems, the user can choose any one of the four basic algorithms namely, Segregated Fully Implicit Backward Time Central Space Scheme, Coupled Fully Implicit Backward Time Central Space Scheme, Segregated Semi-Implicit Backward Time Central Space Scheme and Coupled Semi-Implicit Backward Time Space Scheme.

15. Efficient solution to linear systems arising from discretized momentum and pressure equations. The use can switch between Gauss-Seidel approach and Krylov solvers implemented via LiS library for this purpose. The latter offers several alternatives and is open-source third-party software.

16. User can couple one or more modules to accomplish genuinely multiphysics simulations of interest via UDFs.