multiheats 0.401

MultIHeaTS is a Multi-layered Implicit Heat Transfer Solver.

MultIHeaTS

MultIHeaTS is a Multi-layered Implicit Heat Transfer Solver.

It is an implicit numerical model that simulates and predicts the surface temperature in 1D multi-layered planetary surfaces exposed to solar radiation.

Getting started • Installation • How to Use • Configuration • License

Getting Started

Showcase of what the solver can output for a bi-layer surface profile on Japet. Note that here the interface is located around 32 cm. Additional figures may be found in the examples directory.

Dependencies

• a shell
• git
• conda

You can find conda at https://www.anaconda.com/ although I would suggest installing it directly from the command line. Make sure conda is installed by tiping:

conda

It should return a help message.

Installation

Copy the project localy using git clone:

git clone [e-mail]:cyril.mergny/multiheats.git

then cd to the path of the repositery on you computer

cd path_to_multiheats/

Then install the required conda environment ( an alternative method using pip is in WIP):

conda env create -f environment.yml

Finally you need to make multiheats a python package by typing:

pip install -e .

(It is in my plans to replace the conda env by packaging all dependancies in pip.)

How to use

Make sure to activate the conda environment before executing anything:

conda activate multitheats

There is an example script that you can run to see what the algorithm ouptut for a pre-defined profile.

cd path_to_multiheats/examples/
./run_example.sh

After iterating over all timestep the script should output matplotlib figures.

For more advance usage I recommand executing python directly in the src folder:

cd path_to_multiheats/src/multiheats/
python main.py

Configuration

Currently you need to write you own personal modifications directly in the python scripts. A configuration file may come in later commits.

Changing the Simulation Parameters

The latitude, longitude, emissivity of the surface, and the space array can be modified in the init method of the Profile class.

def __init__(self) -> None:
    self.nx = 100
    self.lat = 0
    self.long = 0
    self.eps = 0.94  # Emissivity
    x0 = 0  # Surface depth (m)
    xf = 10  # Total depth (m)

    power = 4
    self.qheat = np.full(self.nx, 0)
    spaces = np.linspace(x0, xf ** (1 / power), self.nx)
    self.spaces = spaces ** (power)
    # prof.spaces = np.linspace(0, 2, self.nx)

Changing the Surface Profiles

The solver is meant to be working for any type of multi-layered surfaces. The surface material property profiles may be changed directly inside the create_profile.py python script.

For example to change the values of an homegeneous profile, change the variables cond, rho, cp in the method monolayer_prof()

def monolayer_prof(self):
    """
    Generate an monolayered surface profile.
    PARAMS:
        cond - Conductivity (W.m-1.K-2)
        rho - Density (kg,m-3)
        cp - Heat capacity (J.kg-1.K-1)
    """
    cond = 0.01
    rho = 917.0
    cp = 839.0

    self.cond = np.full(self.nx, cond)
    self.rho = np.full(self.nx, rho)
    self.cp = np.full(self.nx, cp)

The same can be done for the bilayer profile: tweak the parameters in the method bilayer_prof().

For any types of other exotic profiles (3 layers, etc...), feel free to write you own method in Profile class.

Changing the Surface Flux

Flux are imported by the solar_flux.py module. Currently, the scripts import Japet solar flux and albedos from files in the data directory.

Changing the Boundary Conditions

I would not recommend tweaking with the solvers.py module unless you know what you are doing. Anyway, the top and bottom boundary conditions may be change in the set_flux_BC() method.

def set_flux_BC(self, matrice, source, dt):
    """
    Set boundary conditions for implicit Euler Scheme
    Imposed flux or imposed temperature possible.
    """
    rcoef = dt / self.rho / self.cp
    cond = self.cond

    # Set Boundary conditions
    bc_top = self.solar_flux / cond[0]
    bc_top += self.eps * cst.SIGMA / self.cond[0] * self.temp[0] ** 4
    self.bc_top = bc_top
    bc_bottom = 0
    ...

For example to add a radioactive thermal flux coming from the planet interior change bc_bottom to the flux' value.

The solvers is supposed to work with flux or temperature boundary conditions. Although for the second case some additional modifications may be required to make the solver work.

Changing the Plot

Just modify or write you own functions in the visualise.py module.

Changing the Main

Finally you may change other simulations parameters directly in the main.py script. For example, use it to switch between a monolayer or bilayer profile. Or to change the number of timestep used for iterations.

Contributing

Contributions are welcome:

• Feel free to open an issue for feedback about usability.
• You may fork the project as you wish as long as you cite the original in your research.
• Pull request may be accepted if new features are in the scope of the MultIHeaTS core.

Please keep pull requests focused and don't change multiple things at the same time.

Citation

Article Submitted to Computational Geoscience !

License

MultIHeaTS is distributed under the terms of the GNU GPL License Version 3. A complete version of the license is available in the COPYING file in this repository. Any contribution made to this project will be licensed under the GNU GPL License Version 3.