wavy

wavy

A spectral ocean wave modeling framework.

• Getting started
• Building wavy
• Building a simple program with wavy
• Examples
• Design principles
• Features
• Development status

Getting started

Building wavy

git clone --recursive https://github.com/wavebitscientific/wavy.git
FC=gfortran make
mkdir build
cd build
FC=gfortran cmake ..
make
ctest

Change the FC value if building with a different Fortran compiler.

By default, wavy will be built in single precision (32-bit reals). To build it in double (64-bit reals) or quadruple precision (128-bit reals), use the -DREAL argument when invoking cmake:

FC=gfortran cmake .. -DREAL=64 # for double precision

or:

FC=gfortran cmake .. -DREAL=128 # for quad precision

wavy needs gcc-6.3.0 or later to succesfully build and pass all tests.

Building a simple program with wavy

If you compiled wavy in wavy/build, then the module files and the library are located in wavy/build/include and wavy/build/lib, respectively. For example, if we want to build a simple wavy hello world program from the base directory, we could do it like this:

gfortran hello.f90 -o hello -Ibuild/include -Lbuild/lib -lwavy

Examples

Initialize a omnidirectional spectrum instance in the frequency range from 0.04 to 2 Hz with logarithmic increment of 1.1, in mean water depth of 1000 m:

use mod_spectrum,only:spectrum_type
type(spectrum_type) :: spec

! initialize a spectrum instance
spec = spectrum_type(fmin=0.04,fmax=2.,df=1.1,ndirs=1,depth=1000.)

Same as above, but directional spectrum with 36 directional bins:

spec = spectrum_type(fmin=0.04,fmax=2.,df=1.1,ndirs=36,depth=1000.)

Initialize omnidirectional spectrum with JONSWAP shape at wind speed of 10 m/s, and fetch of 100 km:

use mod_spectrum,only:spectrum_type
use mod_spectral_shapes,only:jonswap

type(spectrum_type) :: spec

! initialize a spectrum instance
spec = spectrum_type(fmin=0.04,fmax=2.,df=1.1,ndirs=1,depth=1000.)

! assign a JONSWAP-shape spectrum to the instance
spec = jonswap(spec % getFrequency(),wspd=10.,fetch=1e5,grav=9.8)

Above examples will work with default precision (REAL32). To write code that is always compatible with precision specified at build time, use mod_precision module:

use mod_precision,only:rk => realkind
use mod_spectrum,only:spectrum_type
use mod_spectral_shapes,only:jonswap

type(spectrum_type) :: spec

! initialize a spectrum instance
spec = spectrum_type(fmin=0.04_rk,fmax=2._rk,df=1.1_rk,ndirs=1,depth=1000._rk)

! assign a JONSWAP-shape spectrum to the instance
spec = jonswap(spec % getFrequency(),wspd=10._rk,fetch=1e5_rk,grav=9.8_rk)

There are many pre-built diagnostics that can be output from a spectrum instance, here is a taste of a few:

write(*,*)'Significant wave height [m]: ',spec % significantWaveHeight()
write(*,*)'       Mean wave period [s]: ',spec % meanPeriod()
write(*,*)'      Mean square slope [-]: ',spec % meanSquareSlope()
write(*,*)'         Stokes drift [m/s]: ',spec % stokesDrift([0._rk])

outputs:

 Significant wave height [m]:    2.13949418    
        Mean wave period [s]:    5.20506239    
       Mean square slope [-]:    2.39831898E-02
          Stokes drift [m/s]:    4.87080999E-02

Design principles

• Pure Fortran goodness
• Object-oriented for high-level abstractions, functional for the computational kernels
• Framework to contruct arbitrary wave models
• Provides a rich set of source functions, parametric shapes, numerical schemes, and wave diagnostics
• Easy to use by existing atmosphere and ocean models
• Supports single (32-bit), double (64-bit), and quadruple (128-bit) precision floating point arithmetic
• Self-documented
• Fully unit-tested

Features

• Classes:

  • [x] Spectrum class: supports omnidirectional and directional spectra
  • [x] Grid class: supports regular 1-d and 2-d grids
  • [x] Domain class: built from Grid and Spectrum instances.

• Source functions:

  • [x] Sin, Sds, Sdt, Snl, Sbf (Donelan et al., 2012)
  • [ ] Sin, Sds, WAM cycle 3 (Komen et al., 1984)
  • [ ] Sin, Sds (Tolman and Chalikov, 1996)
  • [ ] Sin, Sds, WAM cycle 4 (Janssen, 2004)
  • [ ] Sin, Sds, (Ardhuin et al., 2010)
  • [ ] Snl (Donelan et al., 2012)
  • [ ] Snl, DIA (Hasselmann et al., 1985)

• Parametric spectra:

  • [x] Donelan, Hamilton & Hui (1985)
  • [x] JONSWAP (1973)
  • [x] Phillips (1956)
  • [x] Pierson-Moskowitz (1964)

• Grid projections:

  • [x] Cartesian
  • [ ] Spherical

• Time integration scheme:

  • [x] First order, forward Euler (explicit)
  • [x] First order, backward Euler (implicit)
  • [x] Exact exponential

• Advection schemes:

  • [x] Upwind differences, 1st order, 1-d
  • [x] Upwind differences, 1st order, 2-d
  • [x] Upwind differences, 2nd order, 1-d
  • [x] Upwind differences, 2nd order, 2-d
  • [x] Centered differences, 2nd order, 1-d
  • [x] Centered differences, 2nd order, 2-d
  • [ ] Flux corrected transport (Zalesak, 1979)
  • [ ] Smolarkiewitz anti-diffusive velocity scheme (Smolarkiewitz, 1981)
  • [ ] MPDATA (Smolarkiewitz, 1983)
  • [ ] ULTIMATE QUICKEST (Wavewatch III)

• Stokes drift:

  • [ ] Monochromatic
  • [x] Exact
  • [ ] Webb and Fox-Kemper (2011)
  • [ ] Breivik et al. (2015)

• Parallel execution:

  • [ ] Fortran Coarrays

• Input/Output:

  • [ ] NetCDF
  • [x] JSON

Development status

wavy is in early development. Contributors are highly needed, especially for implementing source functions. You can start contributing by opening an issue.