Zodiac (DNS code for Ice-ocean boundary layer)

Brief description

From the project summary:
Melting of grounded ice mass in the Arctic and Antarctic may play a key role in future global sea level rise and Earth's climate system. The Antarctic Ice Sheet is losing ice at an increasing rate, primarily due to ocean-driven melting beneath ice shelves. The physics of these ocean-ice interactions is poorly understood which, along with limited observation constraints, leads to uncertainties in the predictions of future melt rate. We will undertake cutting edge direct numerical simulations to examine the complex dynamics of melting of ice-shelves in the presence of convection and turbulence. The project will provide the knowledge base for improved representation of these Antarctic processes in future global ocean models from which more accurate projections of future climate and sea level will follow.

Description of the Code: Zodiac is a pseudo spectral code with adjustable choices of domain periodicity. It is mainly developed for analyzing boundary layer turbulence with complex geometry. It uses a Rk3 solver, ADI for the the nonlinear terms and Multi-grid for convergence. It is MPI parallelised and the domain-decomposition can be customised based on the needs. The structure of the code is briefly described here. zodiac.F90: It is the main program that initialise the code and get input parameters (input.dat, grid_def), calls in the solver, manages output. duct.F90: solves the RK3 steps of the NS equations, uses FFT, calls in ADI for the implicit non-linear part, uses Multi-grid for faster convergence, deals with different forcing (written inside the same files as subroutines, viz. wave_forcing) boundary.F90: Provides the boundary conditions, in the present case it has been used to study the melting problem in the ice-water interface. It can be customised based on the problem). flow_statistics.F90: Deals with the tke and energy budget of the flow. It also stitches the decomposed domain from other processors. flow_output.F90: Deals with the output, presently it can output in .plt (for tecplot, that need tecio64.a files), .vtk(for preview) and also for netcdf(to be added as a patch). GRID_XY.dat: It is the main grid file for the present problem, that can be customized. Required Libraries: gcc/4.9.3 (or higher) netcdf-fortran fftw2 (the code is not compatible with fftw3) openmpi(1.10.2 or higher, for multiprocessing) tecplot library file (tecio64.a) The uses needs to create the blank directories: plane_data, plane_tke, last_saved The code can be downloaded from the github repository: https://github.com/mmainak/zodiac2